diff --git a/zlib.c b/zlib.c
index bbaa0815ed..61e6df0fdc 100644
--- a/zlib.c
+++ b/zlib.c
@@ -189,7 +189,7 @@ void git_deflate_init_gzip(git_zstream *strm, int level)
 	 * Use default 15 bits, +16 is to generate gzip header/trailer
 	 * instead of the zlib wrapper.
 	 */
-	return do_git_deflate_init(strm, level, 15 + 16);
+	do_git_deflate_init(strm, level, 15 + 16);
 }
 
 void git_deflate_init_raw(git_zstream *strm, int level)
@@ -198,7 +198,7 @@ void git_deflate_init_raw(git_zstream *strm, int level)
 	 * Use default 15 bits, negate the value to get raw compressed
 	 * data without zlib header and trailer.
 	 */
-	return do_git_deflate_init(strm, level, -15);
+	do_git_deflate_init(strm, level, -15);
 }
 
 int git_deflate_abort(git_zstream *strm)