Deep levels in MOCVD grown p-InP on GaAs substrates have been investigated by Deep Level Transient Spectroscopy (DLTS). The effect of hydrogenation on the electrical activity of these levels has been studied through a combination of DLTS and Photoluminescence (PL) measurements. DLTS measurements indicate a drop of trap density from σ 5 × 1014 cm−3 to σ 1 × 1012 cm−3 after hydrogenation. Annealing at 400°C reactivated only the dopants, while temperatures above 600°C were necessary for deep-level reactivation. This combined with a logarithmic dependence on fill pulse time, indicate that at least one broad DLTS peak is associated with dislocations. The PL the DLTS results show that the dislocation related traps are passivated by hydrogen, preferentially over the dopants and that a wide annealing window exists for dopant reactivation.