diff --git a/src/lib/http/client.cc b/src/lib/http/client.cc
index 6067898ad3..7b7a9d4687 100644
--- a/src/lib/http/client.cc
+++ b/src/lib/http/client.cc
@@ -1763,7 +1763,7 @@ public:
             conn_pool_.reset(new ConnectionPool(*thread_io_service_, thread_pool_size_));
 
             LOG_DEBUG(http_logger, isc::log::DBGLVL_TRACE_BASIC, HTTP_CLIENT_MT_STARTED)
-                     .arg(getThreadCount());
+                     .arg(thread_pool_size_);
         } else {
             // Single-threaded mode: use the caller's IOService,
             // one connection per URL.