diff --git a/src/internfile/mh_exec.cpp b/src/internfile/mh_exec.cpp
index 0b5774bc..329a88fb 100644
--- a/src/internfile/mh_exec.cpp
+++ b/src/internfile/mh_exec.cpp
@@ -25,6 +25,7 @@ static char rcsid[] = "@(#$Id: mh_exec.cpp,v 1.14 2008-10-09 09:19:37 dockes Exp
 #include "cancelcheck.h"
 #include "smallut.h"
 #include "transcode.h"
+#include "md5.h"
 
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -130,5 +131,14 @@ bool MimeHandlerExec::next_document()
     // could still be overridden by the content-type meta tag.
     m_metaData["charset"] = charset;
     m_metaData["mimetype"] = mt;
+
+    string md5, xmd5, reason;
+    if (MD5File(m_fn, md5, &reason)) {
+	m_metaData["md5"] = MD5HexPrint(md5, xmd5);
+    } else {
+	LOGERR(("MimeHandlerExec: cant compute md5 for [%s]: %s\n", 
+		m_fn.c_str(), reason.c_str()));
+    }
+
     return true;
 }
diff --git a/src/internfile/mh_html.cpp b/src/internfile/mh_html.cpp
index 2c9140cb..48cc173c 100644
--- a/src/internfile/mh_html.cpp
+++ b/src/internfile/mh_html.cpp
@@ -29,6 +29,7 @@ static char rcsid[] = "@(#$Id: mh_html.cpp,v 1.26 2008-10-03 06:17:46 dockes Exp
 #include "indextext.h"
 #include "mh_html.h"
 #include "smallut.h"
+#include "md5.h"
 
 #include <iostream>
 
@@ -53,6 +54,12 @@ bool MimeHandlerHtml::set_document_string(const string& htext)
 {
     m_html = htext;
     m_havedoc = true;
+
+    // We want to compute the md5 now because we may modify m_html later
+    string md5, xmd5;
+    MD5String(htext, md5);
+    m_metaData["md5"] = MD5HexPrint(md5, xmd5);
+
     return true;
 }
 
diff --git a/src/internfile/mh_mail.cpp b/src/internfile/mh_mail.cpp
index 89dad472..789f16af 100644
--- a/src/internfile/mh_mail.cpp
+++ b/src/internfile/mh_mail.cpp
@@ -38,6 +38,7 @@ static char rcsid[] = "@(#$Id: mh_mail.cpp,v 1.35 2008-10-04 14:26:59 dockes Exp
 #include "mh_html.h"
 #include "rclconfig.h"
 #include "mimetype.h"
+#include "md5.h"
 
 // binc imap mime definitions
 #include "mime.h"
@@ -81,6 +82,18 @@ bool MimeHandlerMail::set_document_file(const string &fn)
 	close(m_fd);
 	m_fd = -1;
     }
+
+    // Yes, we read the file twice. It would be possible in theory to add
+    // the md5 computation to the mime analysis, but ...
+    string md5, xmd5, reason;
+    if (MD5File(fn, md5, &reason)) {
+	m_metaData["md5"] = MD5HexPrint(md5, xmd5);
+    } else {
+	LOGERR(("MimeHandlerMail: cant compute md5 for [%s]: %s\n", fn.c_str(),
+		reason.c_str()));
+    }
+
+
     m_fd = open(fn.c_str(), 0);
     if (m_fd < 0) {
 	LOGERR(("MimeHandlerMail::set_document_file: open(%s) errno %d\n",
@@ -104,6 +117,11 @@ bool MimeHandlerMail::set_document_string(const string &msgtxt)
     LOGDEB1(("MimeHandlerMail::set_document_string\n"));
     LOGDEB2(("Message text: [%s]\n", msgtxt.c_str()));
     delete m_stream;
+
+    string md5, xmd5;
+    MD5String(msgtxt, md5);
+    m_metaData["md5"] = MD5HexPrint(md5, xmd5);
+
     m_stream = new stringstream(msgtxt);
     delete m_bincdoc;
     m_bincdoc = new Binc::MimeDocument;
diff --git a/src/internfile/mh_text.cpp b/src/internfile/mh_text.cpp
index 5a76981f..c41430d6 100644
--- a/src/internfile/mh_text.cpp
+++ b/src/internfile/mh_text.cpp
@@ -29,19 +29,26 @@ using namespace std;
 #include "debuglog.h"
 #include "readfile.h"
 #include "transcode.h"
+#include "md5.h"
 
 // Process a plain text file
 bool MimeHandlerText::set_document_file(const string &fn)
 {
     string otext;
-    if (!file_to_string(fn, otext))
+    string reason;
+    if (!file_to_string(fn, otext, &reason)) {
+	LOGERR(("MimeHandlerText: can't read file: %s\n", reason.c_str()));
 	return false;
+    }
     return set_document_string(otext);
 }
     
 bool MimeHandlerText::set_document_string(const string& otext)
 {
     m_text = otext;
+    string md5, xmd5;
+    MD5String(m_text, md5);
+    m_metaData["md5"] = MD5HexPrint(md5, xmd5);
     m_havedoc = true;
     return true;
 }
diff --git a/src/qtgui/guiutils.cpp b/src/qtgui/guiutils.cpp
index f8112317..04ff6914 100644
--- a/src/qtgui/guiutils.cpp
+++ b/src/qtgui/guiutils.cpp
@@ -175,6 +175,8 @@ void rwSettings(bool writing)
     SETTING_RW(prefs.ssearchAutoPhrase, 
 	       "/Recoll/prefs/ssearchAutoPhrase", Bool, false);
     SETTING_RW(prefs.respagesize, "/Recoll/prefs/reslist/pagelen", Num, 8);
+    SETTING_RW(prefs.collapseDuplicates, 
+	       "/Recoll/prefs/reslist/collapseDuplicates", Bool, false);
     SETTING_RW(prefs.maxhltextmbs, "/Recoll/prefs/preview/maxhltextmbs", Num, 3);
     SETTING_RW(prefs.qtermcolor, "/Recoll/prefs/qtermcolor", , "blue");
     if (!writing && prefs.qtermcolor == "")
diff --git a/src/qtgui/guiutils.h b/src/qtgui/guiutils.h
index 93e992a9..9f213773 100644
--- a/src/qtgui/guiutils.h
+++ b/src/qtgui/guiutils.h
@@ -82,6 +82,7 @@ class PrefsPack {
     bool startWithAdvSearchOpen;
     bool startWithSortToolOpen;
     bool previewHtml;
+    bool collapseDuplicates;
     // Extra query indexes. This are encoded to base64 before storing
     // to the qt settings file to avoid any bin string/ charset conv issues
     list<string> allExtraDbs;
diff --git a/src/qtgui/rclmain_w.cpp b/src/qtgui/rclmain_w.cpp
index 41df30e2..d3cea459 100644
--- a/src/qtgui/rclmain_w.cpp
+++ b/src/qtgui/rclmain_w.cpp
@@ -471,6 +471,7 @@ void RclMain::startSearch(RefCntr<Rcl::SearchData> sdata)
     sdata->setStemlang(stemLang);
 
     Rcl::Query *query = new Rcl::Query(rcldb);
+    query->setCollapseDuplicates(prefs.collapseDuplicates);
 
     if (!query || !query->setQuery(sdata)) {
 	QMessageBox::warning(0, "Recoll", tr("Can't start query: ") +
diff --git a/src/qtgui/uiprefs.ui b/src/qtgui/uiprefs.ui
index 334c177f..bb0af112 100644
--- a/src/qtgui/uiprefs.ui
+++ b/src/qtgui/uiprefs.ui
@@ -90,6 +90,20 @@
                                             </widget>
                                         </hbox>
                                     </widget>
+                                    <widget class="QCheckBox">
+                                        <property name="name">
+                                            <cstring>collapseDupsCB</cstring>
+                                        </property>
+                                        <property name="toolTip" stdset="0">
+                                          <string>If checked, results with the same content under different names will only be shown once.</string>
+                                        </property>
+                                        <property name="text">
+                                            <string>Hide duplicate results.</string>
+                                        </property>
+                                        <property name="checked">
+                                            <bool>false</bool>
+                                        </property>
+                                    </widget>
                                     <widget class="QLayoutWidget">
                                         <property name="name">
                                             <cstring>qtermcolor</cstring>
diff --git a/src/qtgui/uiprefs_w.cpp b/src/qtgui/uiprefs_w.cpp
index cffe42f6..33b2b6d2 100644
--- a/src/qtgui/uiprefs_w.cpp
+++ b/src/qtgui/uiprefs_w.cpp
@@ -97,6 +97,7 @@ void UIPrefsDialog::setFromPrefs()
 {
     // Entries per result page spinbox
     pageLenSB->setValue(prefs.respagesize);
+    collapseDupsCB->setChecked(prefs.collapseDuplicates);
     maxHLTSB->setValue(prefs.maxhltextmbs);
     autoSearchCB->setChecked(prefs.autoSearchOnWS);
     syntlenSB->setValue(prefs.syntAbsLen);
@@ -173,6 +174,7 @@ void UIPrefsDialog::accept()
 {
     prefs.autoSearchOnWS = autoSearchCB->isChecked();
     prefs.respagesize = pageLenSB->value();
+    prefs.collapseDuplicates = collapseDupsCB->isChecked();
     prefs.maxhltextmbs = maxHLTSB->value();
 
     prefs.qtermcolor = qtermColorLE->text();
diff --git a/src/rcldb/rcldb.cpp b/src/rcldb/rcldb.cpp
index 1d172d71..1e5cf2fd 100644
--- a/src/rcldb/rcldb.cpp
+++ b/src/rcldb/rcldb.cpp
@@ -48,7 +48,7 @@ using namespace std;
 #include "searchdata.h"
 #include "rclquery.h"
 #include "rclquery_p.h"
-
+#include "md5.h"
 
 #ifndef MAX
 #define MAX(A,B) (A>B?A:B)
@@ -57,15 +57,6 @@ using namespace std;
 #define MIN(A,B) (A<B?A:B)
 #endif
 
-// Omega compatible values. We leave a hole for future omega values. Not sure 
-// it makes any sense to keep any level of omega compat given that the index
-// is incompatible anyway.
-enum value_slot {
-    VALUE_LASTMOD = 0,	// 4 byte big endian value - seconds since 1970.
-    VALUE_MD5 = 1,	// 16 byte MD5 checksum of original document.
-    VALUE_SIG = 10      // Doc sig as chosen by app (ex: mtime+size
-};
-
 // Recoll index format version is stored in user metadata. When this change,
 // we can't open the db and will have to reindex.
 static const string RCL_IDX_VERSION_KEY("RCL_IDX_VERSION_KEY");
@@ -1078,6 +1069,15 @@ bool Db::addOrUpdate(const string &udi, const string &parent_udi,
 	}
     }
 
+    // If the file's md5 was computed, add value. This is optionally
+    // used for query result duplicate elimination.
+    string& md5 = doc.meta[Doc::keymd5];
+    if (!md5.empty()) {
+	string digest;
+	MD5HexScan(md5, digest);
+	newdocument.add_value(VALUE_MD5, digest);
+    }
+
     LOGDEB0(("Rcl::Db::add: new doc record:\n%s\n", record.c_str()));
     newdocument.set_data(record);
 
diff --git a/src/rcldb/rcldb.h b/src/rcldb/rcldb.h
index a1c86415..3f6fc0c5 100644
--- a/src/rcldb/rcldb.h
+++ b/src/rcldb/rcldb.h
@@ -56,6 +56,15 @@ class RclConfig;
 namespace Rcl {
 #endif
 
+// Omega compatible values. We leave a hole for future omega values. Not sure 
+// it makes any sense to keep any level of omega compat given that the index
+// is incompatible anyway.
+enum value_slot {
+    VALUE_LASTMOD = 0,	// 4 byte big endian value - seconds since 1970.
+    VALUE_MD5 = 1,	// 16 byte MD5 checksum of original document.
+    VALUE_SIG = 10      // Doc sig as chosen by app (ex: mtime+size
+};
+
 class SearchData;
 class TermIter;
 class Query;
diff --git a/src/rcldb/rcldoc.cpp b/src/rcldb/rcldoc.cpp
index 8ff4f285..bb50968d 100644
--- a/src/rcldb/rcldoc.cpp
+++ b/src/rcldb/rcldoc.cpp
@@ -22,4 +22,5 @@ namespace Rcl {
     const string Doc::keyau("author");
     const string Doc::keytt("title");
     const string Doc::keykw("keywords");
+    const string Doc::keymd5("md5");
 }
diff --git a/src/rcldb/rcldoc.h b/src/rcldb/rcldoc.h
index 6e15a98f..793d8f19 100644
--- a/src/rcldb/rcldoc.h
+++ b/src/rcldb/rcldoc.h
@@ -157,6 +157,7 @@ class Doc {
     static const string keyau;  // author
     static const string keytt;  // title
     static const string keykw;  // keywords
+    static const string keymd5; // file md5 checksum
 };
 
 
diff --git a/src/rcldb/rclquery.cpp b/src/rcldb/rclquery.cpp
index 5d07029b..88652024 100644
--- a/src/rcldb/rclquery.cpp
+++ b/src/rcldb/rclquery.cpp
@@ -89,7 +89,8 @@ private:
 };
 
 Query::Query(Db *db)
-    : m_nq(new Native(this)), m_db(db), m_sorter(0), m_sortAscending(true)
+    : m_nq(new Native(this)), m_db(db), m_sorter(0), m_sortAscending(true),
+      m_collapseDuplicates(false)
 {
 }
 
@@ -155,7 +156,11 @@ bool Query::setQuery(RefCntr<SearchData> sdata)
     string d;
     try {
 	m_nq->enquire = new Xapian::Enquire(m_db->m_ndb->db);
-	m_nq->enquire->set_query(m_nq->query);
+	if (m_collapseDuplicates) {
+	    m_nq->enquire->set_collapse_key(Rcl::VALUE_MD5);
+	} else {
+	    m_nq->enquire->set_collapse_key(Xapian::BAD_VALUENO);
+	}
 	if (!m_sortField.empty()) {
 	    if (m_sorter) {
 		delete (QSorter*)m_sorter;
@@ -167,6 +172,7 @@ bool Query::setQuery(RefCntr<SearchData> sdata)
 	    m_nq->enquire->set_sort_by_key((QSorter*)m_sorter, 
 					   !m_sortAscending);
 	}
+	m_nq->enquire->set_query(m_nq->query);
 	m_nq->mset = Xapian::MSet();
 	// Get the query description and trim the "Xapian::Query"
 	d = m_nq->query.get_description();
diff --git a/src/rcldb/rclquery.h b/src/rcldb/rclquery.h
index bae86a54..10f7a3bb 100644
--- a/src/rcldb/rclquery.h
+++ b/src/rcldb/rclquery.h
@@ -54,6 +54,7 @@ class Query {
 
     /** Choose sort order. Must be called before setQuery */
     void setSortBy(const string& fld, bool ascending = true);
+    void setCollapseDuplicates(bool on) {m_collapseDuplicates = on;}
     const string& getSortBy() const {return m_sortField;}
     bool getSortAscending() const {return m_sortAscending;}
 
@@ -90,8 +91,9 @@ private:
     string m_reason; // Error explanation
     Db    *m_db;
     void  *m_sorter;
-    string       m_sortField;
-    bool         m_sortAscending;
+    string m_sortField;
+    bool   m_sortAscending;
+    bool   m_collapseDuplicates;     
     /* Copyconst and assignement private and forbidden */
     Query(const Query &) {}
     Query & operator=(const Query &) {return *this;};