diff --git a/include/dbus_monitor.hpp b/include/dbus_monitor.hpp
index 1b82697..cddafc8 100644
--- a/include/dbus_monitor.hpp
+++ b/include/dbus_monitor.hpp
@@ -150,7 +150,7 @@
             nlohmann::json::iterator paths = j.find("paths");
             if (paths != j.end())
             {
-                int interfaceCount = thisSession.interfaces.size();
+                size_t interfaceCount = thisSession.interfaces.size();
                 if (interfaceCount == 0)
                 {
                     interfaceCount = 1;