diff --git a/leveldb/db.go b/leveldb/db.go
index 384c498..24c6ba9 100644
--- a/leveldb/db.go
+++ b/leveldb/db.go
@@ -141,12 +141,12 @@ func (db *DB) NewWriteBatch() *WriteBatch {
 	return wb
 }
 
-//limit <= 0, unlimit
+//limit < 0, unlimit
 func (db *DB) Iterator(min []byte, max []byte, rangeType uint8, limit int) *Iterator {
 	return newIterator(db, db.iteratorOpts, NewRange(min, max, rangeType), limit, IteratorForward)
 }
 
-//limit <= 0, unlimit
+//limit < 0, unlimit
 func (db *DB) RevIterator(min []byte, max []byte, rangeType uint8, limit int) *Iterator {
 	return newIterator(db, db.iteratorOpts, NewRange(min, max, rangeType), limit, IteratorBackward)
 }
diff --git a/leveldb/iterator.go b/leveldb/iterator.go
index 01dd0f4..bb076d1 100644
--- a/leveldb/iterator.go
+++ b/leveldb/iterator.go
@@ -95,7 +95,7 @@ func (it *Iterator) Valid() bool {
 		return false
 	}
 
-	if it.limit > 0 && it.step >= it.limit {
+	if it.limit >= 0 && it.step >= it.limit {
 		return false
 	}
 
diff --git a/leveldb/leveldb_test.go b/leveldb/leveldb_test.go
index 62cd074..2fd4e14 100644
--- a/leveldb/leveldb_test.go
+++ b/leveldb/leveldb_test.go
@@ -146,7 +146,7 @@ func TestIterator(t *testing.T) {
 		return []byte(fmt.Sprintf("key_%d", i))
 	}
 
-	it = db.Iterator(k(1), k(5), RangeClose, 0)
+	it = db.Iterator(k(1), k(5), RangeClose, -1)
 	if err := checkIterator(it, 1, 2, 3, 4, 5); err != nil {
 		t.Fatal(err)
 	}
@@ -156,22 +156,22 @@ func TestIterator(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	it = db.Iterator(k(1), k(5), RangeLOpen, 0)
+	it = db.Iterator(k(1), k(5), RangeLOpen, -1)
 	if err := checkIterator(it, 2, 3, 4, 5); err != nil {
 		t.Fatal(err)
 	}
 
-	it = db.Iterator(k(1), k(5), RangeROpen, 0)
+	it = db.Iterator(k(1), k(5), RangeROpen, -1)
 	if err := checkIterator(it, 1, 2, 3, 4); err != nil {
 		t.Fatal(err)
 	}
 
-	it = db.Iterator(k(1), k(5), RangeOpen, 0)
+	it = db.Iterator(k(1), k(5), RangeOpen, -1)
 	if err := checkIterator(it, 2, 3, 4); err != nil {
 		t.Fatal(err)
 	}
 
-	it = db.RevIterator(k(1), k(5), RangeClose, 0)
+	it = db.RevIterator(k(1), k(5), RangeClose, -1)
 	if err := checkIterator(it, 5, 4, 3, 2, 1); err != nil {
 		t.Fatal(err)
 	}
@@ -181,17 +181,17 @@ func TestIterator(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	it = db.RevIterator(k(1), k(5), RangeLOpen, 0)
+	it = db.RevIterator(k(1), k(5), RangeLOpen, -1)
 	if err := checkIterator(it, 5, 4, 3, 2); err != nil {
 		t.Fatal(err)
 	}
 
-	it = db.RevIterator(k(1), k(5), RangeROpen, 0)
+	it = db.RevIterator(k(1), k(5), RangeROpen, -1)
 	if err := checkIterator(it, 4, 3, 2, 1); err != nil {
 		t.Fatal(err)
 	}
 
-	it = db.RevIterator(k(1), k(5), RangeOpen, 0)
+	it = db.RevIterator(k(1), k(5), RangeOpen, -1)
 	if err := checkIterator(it, 4, 3, 2); err != nil {
 		t.Fatal(err)
 	}