A novel approach to tracking control of a differential robot is proposed. Based on a Port-Hamiltonian representation of a differential robot, canonical transformations are used to obtain a controller that guarantees the tracking of a reference. The control law is inspired by a well-known controller taken from the literature and the Port-Hamiltonian version of the control law is derived. The performance of the algorithm as well as some of the robustness properties are tested using simulations under different scenarios.