diff --git a/index.go b/index.go
index 5245c94..c2be920 100644
--- a/index.go
+++ b/index.go
@@ -93,7 +93,7 @@ func (i *Index) walk() error {
 func (i *Index) write() (err error) {
 	if i.w == nil {
 		const readUserOnly = 0600
-		if i.w, err = os.OpenFile(filepath.Clean(filepath.Join(i.targetDir, "index.md")), os.O_WRONLY|os.O_CREATE, readUserOnly); err != nil {
+		if i.w, err = os.OpenFile(filepath.Clean(filepath.Join(i.targetDir, "index.md")), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, readUserOnly); err != nil {
 			return err
 		}
 	}