diff --git a/Modules/ThirdParty/VNL/src/vxl/core/vnl/vnl_sparse_matrix.txx b/Modules/ThirdParty/VNL/src/vxl/core/vnl/vnl_sparse_matrix.txx
index a94889c7622..8f54a10c53d 100644
--- a/Modules/ThirdParty/VNL/src/vxl/core/vnl/vnl_sparse_matrix.txx
+++ b/Modules/ThirdParty/VNL/src/vxl/core/vnl/vnl_sparse_matrix.txx
@@ -157,7 +157,7 @@ void vnl_sparse_matrix<T>::mult(unsigned int prows, unsigned int pcols,
   assert(prows == columns());
 
   // Clear q matrix.
-  int size = prows*pcols;
+  int size = rows()*pcols;
   for (int temp=0; temp<size; temp++)
     q[temp] = T(0);