diff --git a/gtsam/hybrid/HybridFactor.cpp b/gtsam/hybrid/HybridFactor.cpp
index 1216fd922..b25e97f05 100644
--- a/gtsam/hybrid/HybridFactor.cpp
+++ b/gtsam/hybrid/HybridFactor.cpp
@@ -81,7 +81,7 @@ bool HybridFactor::equals(const HybridFactor &lf, double tol) const {
 /* ************************************************************************ */
 void HybridFactor::print(const std::string &s,
                          const KeyFormatter &formatter) const {
-  std::cout << s;
+  std::cout << (s.empty() ? "" : s + "\n");
   if (isContinuous_) std::cout << "Continuous ";
   if (isDiscrete_) std::cout << "Discrete ";
   if (isHybrid_) std::cout << "Hybrid ";