diff --git a/libs/ardour/ardour/types.h b/libs/ardour/ardour/types.h
index 7fdccac521..11d784079d 100644
--- a/libs/ardour/ardour/types.h
+++ b/libs/ardour/ardour/types.h
@@ -409,7 +409,7 @@ class CueMarker {
 	samplepos_t _position;
 };
 
-typedef std::vector<CueMarker> CueMarkers;
+typedef std::set<CueMarker> CueMarkers;
 
 /*
   Slowest = 6.6dB/sec falloff at update rate of 40ms
diff --git a/libs/ardour/sndfilesource.cc b/libs/ardour/sndfilesource.cc
index cc843260ba..0a66041ee5 100644
--- a/libs/ardour/sndfilesource.cc
+++ b/libs/ardour/sndfilesource.cc
@@ -406,7 +406,7 @@ SndFileSource::open ()
 		if (sf_command (_sndfile, SFC_GET_CUE, &cues, sizeof (SF_CUES)) == SF_TRUE) {
 			cerr << "Found " << cues.cue_count << " cues !\n";
 			for (size_t n = 0; n < cues.cue_count; ++n) {
-				_cue_markers.push_back (CueMarker (string_compose (X_("cue %1"), n+1), cues.cue_points[n].sample_offset));
+				_cue_markers.insert (CueMarker (string_compose (X_("cue %1"), n+1), cues.cue_points[n].sample_offset));
 			}
 		}
 	}