diff --git a/gtsam/hybrid/GaussianMixture.cpp b/gtsam/hybrid/GaussianMixture.cpp
index 4819eda65..0b6fcdff7 100644
--- a/gtsam/hybrid/GaussianMixture.cpp
+++ b/gtsam/hybrid/GaussianMixture.cpp
@@ -105,7 +105,7 @@ bool GaussianMixture::equals(const HybridFactor &lf, double tol) const {
 /* *******************************************************************************/
 void GaussianMixture::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 ";
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 ";