diff --git a/graphics/apngasm/Makefile b/graphics/apngasm/Makefile
index 43d22ae5d475..f6e334115073 100644
--- a/graphics/apngasm/Makefile
+++ b/graphics/apngasm/Makefile
@@ -19,6 +19,8 @@ NO_WRKSUBDIR=	yes
 USE_ZIP=	yes
 USES=		dos2unix gmake
 
+LDFLAGS+=	-lz
+
 PORTDOCS=	readme.txt
 PLIST_FILES=	bin/${PORTNAME}