traditionally, postoperative pain has not been well controlled, pain is an outward manifestation of stress response to surgery, the goal to treat postoperative pain is to eliminate, reduce and relieve and the patient with a minimum of side effects or adverse economic and methods. nsaids have significant value as an alternative of non-opioid analgesic in postoperative pain and can be safely used if contraindications are respected and lower doses are appropriate. materials and methods: this a multicentric, open, prospective study. a 165 patients were colected with diagnosis of moderate to severe postoperative pain to severe or vas 60 to 100 mm, which were administered either im or iv dose of diclofenac potassium (diklason？) 75 mg; the pain intensity was measured by vas 0-100, pid, spid, pid, pain relief and totpar scales. the reviews were conducted at baseline, 0.5, 1, 2, 4, 6, 8 and 12 h after administration of doses evaluated. direct examinations of the side effects, evaluate safety. results: an evident reduction on pain levels was observed from the early 30 min of diclofenac potassium administration. this reduction were significant in all evaluated periods and persisted until 12 hours post administration dose. the 81,21% of the patients experienced improvement in pain relief from the 30 min post dose. significant changes on pain intensity in all periods and all evaluative pain scales studied were showed. the patients opinion about pain relief was very good and good in 79.39% (44.24 very good and 35.15% good) of them. no rescue analgesic therapy was used in the 73% of patients. a single failure rate of 1.81% was observed and 1 only slight adverse effect was reported. conclusions: the use of diclofenac potassium (diklason？), for handling postoperative pain demostrated was safe, effective, fast, and durable.