diff --git a/tsdb/engine/tsm1/compact.go b/tsdb/engine/tsm1/compact.go
index 0fa48fd870..acc888bc2c 100644
--- a/tsdb/engine/tsm1/compact.go
+++ b/tsdb/engine/tsm1/compact.go
@@ -1280,6 +1280,7 @@ func (k *tsmKeyIterator) hasMergedValues() bool {
 
 // Next returns true if there are any values remaining in the iterator.
 func (k *tsmKeyIterator) Next() bool {
+RETRY:
 	// Any merged blocks pending?
 	if len(k.merged) > 0 {
 		k.merged = k.merged[1:]
@@ -1414,6 +1415,12 @@ func (k *tsmKeyIterator) Next() bool {
 
 	k.merge()
 
+	// After merging all the values for this key, we might not have any.  (e.g. they were all deleted
+	// through many tombstones).  In this case, move on to the next key instead of ending iteration.
+	if len(k.merged) == 0 {
+		goto RETRY
+	}
+
 	return len(k.merged) > 0
 }
 
diff --git a/tsdb/engine/tsm1/compact_test.go b/tsdb/engine/tsm1/compact_test.go
index d6c591d5bf..e3608f9837 100644
--- a/tsdb/engine/tsm1/compact_test.go
+++ b/tsdb/engine/tsm1/compact_test.go
@@ -1022,6 +1022,89 @@ func TestTSMKeyIterator_MultipleKeysDeleted(t *testing.T) {
 	}
 }
 
+// Tests that deleted keys are not seen during iteration with
+// TSM files.
+func TestTSMKeyIterator_SingleDeletes(t *testing.T) {
+	dir := MustTempDir()
+	defer os.RemoveAll(dir)
+
+	v1 := tsm1.NewValue(10, int64(1))
+	v2 := tsm1.NewValue(20, int64(1))
+	v3 := tsm1.NewValue(30, int64(1))
+	v4 := tsm1.NewValue(40, int64(1))
+	v5 := tsm1.NewValue(50, int64(1))
+	v6 := tsm1.NewValue(60, int64(1))
+
+	points1 := map[string][]tsm1.Value{
+		"cpu,host=0#!~#value": []tsm1.Value{v1, v2},
+		"cpu,host=A#!~#value": []tsm1.Value{v5, v6},
+		"cpu,host=B#!~#value": []tsm1.Value{v3, v4},
+		"cpu,host=C#!~#value": []tsm1.Value{v1, v2},
+		"cpu,host=D#!~#value": []tsm1.Value{v1, v2},
+	}
+
+	r1 := MustTSMReader(dir, 1, points1)
+
+	if e := r1.DeleteRange([][]byte{[]byte("cpu,host=A#!~#value")}, 50, 50); nil != e {
+		t.Fatal(e)
+	}
+	if e := r1.DeleteRange([][]byte{[]byte("cpu,host=A#!~#value")}, 60, 60); nil != e {
+		t.Fatal(e)
+	}
+	if e := r1.DeleteRange([][]byte{[]byte("cpu,host=C#!~#value")}, 10, 10); nil != e {
+		t.Fatal(e)
+	}
+	if e := r1.DeleteRange([][]byte{[]byte("cpu,host=C#!~#value")}, 60, 60); nil != e {
+		t.Fatal(e)
+	}
+	if e := r1.DeleteRange([][]byte{[]byte("cpu,host=C#!~#value")}, 20, 20); nil != e {
+		t.Fatal(e)
+	}
+
+	iter, err := tsm1.NewTSMKeyIterator(1, false, nil, r1)
+	if err != nil {
+		t.Fatalf("unexpected error creating WALKeyIterator: %v", err)
+	}
+
+	var readValues int
+	var data = []struct {
+		key   string
+		value tsm1.Value
+	}{
+		{"cpu,host=0#!~#value", v1},
+		{"cpu,host=B#!~#value", v3},
+		{"cpu,host=D#!~#value", v1},
+	}
+
+	for iter.Next() {
+		key, _, _, block, err := iter.Read()
+		if err != nil {
+			t.Fatalf("unexpected error read: %v", err)
+		}
+
+		values, err := tsm1.DecodeBlock(block, nil)
+		if err != nil {
+			t.Fatalf("unexpected error decode: %v", err)
+		}
+
+		if exp, got := string(key), data[0].key; exp != got {
+			t.Fatalf("key mismatch: got %v, exp %v", exp, got)
+		}
+
+		if exp, got := len(values), 2; exp != got {
+			t.Fatalf("values length mismatch: exp %v, got %v", exp, got)
+		}
+		readValues++
+
+		assertValueEqual(t, values[0], data[0].value)
+		data = data[1:]
+	}
+
+	if exp, got := 3, readValues; exp != got {
+		t.Fatalf("failed to read expected values: exp %v, got %v", exp, got)
+	}
+}
+
 // Tests that the TSMKeyIterator will abort if the interrupt channel is closed
 func TestTSMKeyIterator_Abort(t *testing.T) {
 	dir := MustTempDir()