NSAID that has analgesic and antiinjlamatuary effects via inhibiting prostaglandins , are frequently prescribed for chronic and acute pain. Although wellknown gastric side effects, systemic blood pressure has not been paid attented effectively. In the literature, there is limited data about effects of COX selective NSAID on blood pressure. In our study normatensive 52 patients using nimesulid and naproxane sodium with similir features of generalised osteoathritis, ambulatuary blood pressure were measured. As a result, COX selective—nimesulid has little effect than COX-unselective naproxane