The aim of this study was to evaluate the analgesic effect of topical ketorolac tromethamine 0.5% during scatter laser photocoagulation procedure in proliferative diabetic retinopathy patients. 60 eyes of 30 consecutive proliferative diabetic retinopathy patients were included to this prospective, randomized, double-masked, controlled study. One (1) h before laser treatment session, ketorolac tromethamine 0.5% was instilled to 1 eye and artificial tear drop to the fellow eye. Just after treatment, the patients were asked for the severity of pain in both eyes. Visual analog scale was used to assess the level of pain. Mean pain level for placebo-instilled eyes was 4.88+/-2.56 and ketorolac instilled eyes were 4.45+/-2.25. There was no significant difference for pain levels between placebo and ketorolac-instilled eyes (P=0.29). Topical ketorolac tromethamine usage is no more effective than artificial tears for pain relief during posterior segment laser procedures in proliferative diabetic retinopathy patients.