To test the hypothesis that rocuronium added to a mixture of local anaesthetics could improve akinesia in Peribulbar Block (PB) we designed this prospective, randomized, double-blinded study. Sixty ASA physical status I and II patients presenting for cataract surgery (manual extracapsular lens extraction) under PB were included. Patients were randomized to 2 groups: rocuronium group (n = 30) received PB with a local anesthetic mixture (Lidocaine 2% + Bupivacaine 0.5%) to which was added 0.06 mg/Kg of rocuronium and control group (n = 30) received PB with the same mixture to which was added saline. Akinesia was assessed with a 12-point scale at 2, 5 and 10 minutes after injection (each of the four rectus muscles and each lid was scored from 0 to 2; 0 = total akinesia, 1 = partial akinesia, 2 = no akinesia). The need for supplementary injection, adverse effects and complications were also recorded. Rocuronium group demonstrated significantly better akinesia scores than control group at 2, 5 and 10 minutes post PB (p < 0.05). Supplementary injection was necessary in 4 patients (13%) in rocuronium group versus 12 patients (40%) in control group (p = 0.039). No significant complications were recorded. Rocuronium added to a mixture of local anaesthetics at a dose of 0.06 mg/Kg improved the quality of akinesia in PB and reduced the need for supplementary injections.