diff --git a/gtsam/hybrid/HybridGaussianConditional.cpp b/gtsam/hybrid/HybridGaussianConditional.cpp
index ac03bd3a3..1bec42810 100644
--- a/gtsam/hybrid/HybridGaussianConditional.cpp
+++ b/gtsam/hybrid/HybridGaussianConditional.cpp
@@ -322,8 +322,11 @@ HybridGaussianConditional::shared_ptr HybridGaussianConditional::prune(
           const GaussianFactorValuePair &pair) -> GaussianFactorValuePair {
     if (max->evaluate(choices) == 0.0)
       return {nullptr, std::numeric_limits<double>::infinity()};
-    else
-      return pair;
+    else {
+      // Add negLogConstant_ back so that the minimum negLogConstant in the
+      // HybridGaussianConditional is set correctly.
+      return {pair.first, pair.second + negLogConstant_};
+    }
   };
 
   FactorValuePairs prunedConditionals = factors().apply(pruner);
diff --git a/gtsam/hybrid/tests/testHybridGaussianConditional.cpp b/gtsam/hybrid/tests/testHybridGaussianConditional.cpp
index e29c485af..350bc9184 100644
--- a/gtsam/hybrid/tests/testHybridGaussianConditional.cpp
+++ b/gtsam/hybrid/tests/testHybridGaussianConditional.cpp
@@ -275,6 +275,11 @@ TEST(HybridGaussianConditional, Prune) {
 
     // Check that the pruned HybridGaussianConditional has 2 conditionals
     EXPECT_LONGS_EQUAL(2, pruned->nrComponents());
+
+    // Check that the minimum negLogConstant is set correctly
+    EXPECT_DOUBLES_EQUAL(
+        hgc.conditionals()({{M(1), 0}, {M(2), 1}})->negLogConstant(),
+        pruned->negLogConstant(), 1e-9);
   }
   {
     const std::vector<double> potentials{0.2, 0, 0.3, 0,  //
@@ -285,6 +290,9 @@ TEST(HybridGaussianConditional, Prune) {
 
     // Check that the pruned HybridGaussianConditional has 3 conditionals
     EXPECT_LONGS_EQUAL(3, pruned->nrComponents());
+
+    // Check that the minimum negLogConstant is correct
+    EXPECT_DOUBLES_EQUAL(hgc.negLogConstant(), pruned->negLogConstant(), 1e-9);
   }
 }