diff --git a/src/tools/imgtool/imgtool.cpp b/src/tools/imgtool/imgtool.cpp
index 322dbe8175d..d5ee821315d 100644
--- a/src/tools/imgtool/imgtool.cpp
+++ b/src/tools/imgtool/imgtool.cpp
@@ -67,18 +67,6 @@ char *strncpyz(char *dest, const char *source, size_t len)
 	return s;
 }
 
-char *strncatz(char *dest, const char *source, size_t len)
-{
-	size_t l;
-	l = strlen(dest);
-	dest += l;
-	if (len > l)
-		len -= l;
-	else
-		len = 0;
-	return strncpyz(dest, source, len);
-}
-
 //-------------------------------------------------
 //  markerrorsource - marks where an error source
 //-------------------------------------------------
diff --git a/src/tools/imgtool/imgtool.h b/src/tools/imgtool/imgtool.h
index fb1b6023fff..5f5da586da5 100644
--- a/src/tools/imgtool/imgtool.h
+++ b/src/tools/imgtool/imgtool.h
@@ -265,7 +265,6 @@ int imgtool_validitychecks(void);
 void unknown_partition_get_info(const imgtool_class *imgclass, uint32_t state, union imgtoolinfo *info);
 
 char *strncpyz(char *dest, const char *source, size_t len);
-char *strncatz(char *dest, const char *source, size_t len);
 void rtrim(char *buf);
 
 #endif /* IMGTOOL_H */