diff --git a/coreutils/tr.c b/coreutils/tr.c
index 563ee0837..89fe3f5b0 100644
--- a/coreutils/tr.c
+++ b/coreutils/tr.c
@@ -160,7 +160,7 @@ static int complement(unsigned char *buffer, unsigned int buffer_len)
 extern int tr_main(int argc, char **argv)
 {
 	register unsigned char *ptr;
-	unsigned int output_length, input_length;
+	unsigned int output_length=0, input_length;
 	int index = 1;
 	short i;
 
diff --git a/tr.c b/tr.c
index 563ee0837..89fe3f5b0 100644
--- a/tr.c
+++ b/tr.c
@@ -160,7 +160,7 @@ static int complement(unsigned char *buffer, unsigned int buffer_len)
 extern int tr_main(int argc, char **argv)
 {
 	register unsigned char *ptr;
-	unsigned int output_length, input_length;
+	unsigned int output_length=0, input_length;
 	int index = 1;
 	short i;