diff --git a/internal/multi_thread_gemm.h b/internal/multi_thread_gemm.h
index 97183e7..711b2c6 100644
--- a/internal/multi_thread_gemm.h
+++ b/internal/multi_thread_gemm.h
@@ -402,7 +402,7 @@ class WorkersPool {
     CreateWorkers(workers_count);
     assert(workers_count <= workers_.size());
     counter_to_decrement_when_ready_.Reset(workers_count);
-    for (int i = 0; i < tasks_count - 1; i++) {
+    for (size_t i = 0; i < tasks_count - 1; i++) {
       workers_[i]->StartWork(tasks[i]);
     }
     // Execute the remaining workload immediately on the current thread.