diff --git a/gtsam/hybrid/HybridConditional.cpp b/gtsam/hybrid/HybridConditional.cpp
index f57237e93..2228b8cdc 100644
--- a/gtsam/hybrid/HybridConditional.cpp
+++ b/gtsam/hybrid/HybridConditional.cpp
@@ -22,6 +22,8 @@
 #include <gtsam/inference/Conditional-inst.h>
 #include <gtsam/inference/Key.h>
 
+#include <iostream>
+#include <memory>
 #include <string>
 
 namespace gtsam {