diff --git a/gtsam/symbolic/SymbolicConditional.h b/gtsam/symbolic/SymbolicConditional.h
index 410784684..2de00f5c3 100644
--- a/gtsam/symbolic/SymbolicConditional.h
+++ b/gtsam/symbolic/SymbolicConditional.h
@@ -78,6 +78,9 @@ namespace gtsam {
 
     virtual ~SymbolicConditional() {}
 
+    /// Copy this object as its actual derived type.
+    SymbolicFactor::shared_ptr clone() const { return boost::make_shared<This>(*this); }
+
     /// @}
 
     /// @name Testable
diff --git a/gtsam/symbolic/SymbolicFactor.h b/gtsam/symbolic/SymbolicFactor.h
index 36a96f9c0..a9551d5f9 100644
--- a/gtsam/symbolic/SymbolicFactor.h
+++ b/gtsam/symbolic/SymbolicFactor.h
@@ -20,6 +20,7 @@
 #include <utility>
 #include <boost/shared_ptr.hpp>
 #include <boost/assign/list_of.hpp>
+#include <boost/make_shared.hpp>
 
 #include <gtsam/inference/Factor.h>
 #include <gtsam/inference/Key.h>
@@ -76,6 +77,9 @@ namespace gtsam {
 
     virtual ~SymbolicFactor() {}
 
+    /// Copy this object as its actual derived type.
+    SymbolicFactor::shared_ptr clone() const { return boost::make_shared<This>(*this); }
+
     /// @}
 
     /// @name Testable