diff --git a/src/ctr_encode_msgpack.c b/src/ctr_encode_msgpack.c
index 4c86360..63714b0 100644
--- a/src/ctr_encode_msgpack.c
+++ b/src/ctr_encode_msgpack.c
@@ -424,7 +424,12 @@ static void pack_scope_spans(mpack_writer_t *writer, struct cfl_list *scope_span
 
         /* scope */
         mpack_write_cstr(writer, "scope");
-        pack_instrumentation_scope(writer, scope_span->instrumentation_scope);
+        if (scope_span->instrumentation_scope != NULL) {
+            pack_instrumentation_scope(writer, scope_span->instrumentation_scope);
+        }
+        else {
+            mpack_write_nil(writer);
+        }
 
         /* spans */
         mpack_write_cstr(writer, "spans");