diff --git a/include/crocoddyl/multibody/residuals/state.hxx b/include/crocoddyl/multibody/residuals/state.hxx
index 244681b7d5..233f5e803b 100644
--- a/include/crocoddyl/multibody/residuals/state.hxx
+++ b/include/crocoddyl/multibody/residuals/state.hxx
@@ -147,11 +147,11 @@ ResidualModelStateTpl<Scalar>::get_reference() const {
 
 template <typename Scalar>
 void ResidualModelStateTpl<Scalar>::set_reference(const VectorXs& reference) {
-  if (static_cast<std::size_t>(reference.size()) != nr_) {
+  if (static_cast<std::size_t>(reference.size()) != state_->get_nx()) {
     throw_pretty("Invalid argument: "
                  << "the state reference has wrong dimension ("
                  << reference.size()
-                 << " provided - it should be " + std::to_string(nr_) + ")")
+                 << " provided - it should be " + std::to_string(state_->get_nx() + ")")
   }
   xref_ = reference;
 }