1 files changed, 5 insertions, 3 deletions
diff --git a/src/env.c b/src/env.c
index 09a91d6a..19e2abe8 100644
--- a/src/env.c
+++ b/src/env.c
@@ -112,9 +112,11 @@ serd_env_add(SerdEnv*        env,
 {
 	SerdPrefix* const prefix = serd_env_find(env, name->buf, name->n_bytes);
 	if (prefix) {
-		SerdNode old_prefix_uri = prefix->uri;
-		prefix->uri = serd_node_copy(uri);
-		serd_node_free(&old_prefix_uri);
+		if (!serd_node_equals(&prefix->uri, uri)) {
+			SerdNode old_prefix_uri = prefix->uri;
+			prefix->uri = serd_node_copy(uri);
+			serd_node_free(&old_prefix_uri);
+		}
 	} else {
 		env->prefixes = (SerdPrefix*)realloc(
 			env->prefixes, (++env->n_prefixes) * sizeof(SerdPrefix));