A flow-injection UV spectrophotometric method for the determination of ketoprofen in gels and ampules was developed. Quantitative determination of ketoprofen was realized by using distilled water as a carrier for gels and citrate buffer, pH 6.5, for ampules at 261 mm. No spectrophotometric interferences from additives of gels, carboxypolymethylene and triethanolamine, were observed. There were also no spectrophotometric, interferences resulting from additives of ampules named as benzyl alcohol and arginine. The detection limits were 0.436 and 0.303 mu g/ml for gels and ampules, respectively. Throughout the study, the flow rate, loop volume and the number of injection per hour were 13.8 ml min(-1), 193 mu l and 85, respectively. Analytical signal of the ketoprofen was linear in the concentration range of 7.5-75 mu g/ml. Quantitative results of ketoprofen in gels, 25.25 +/- 0.27 (mean +/- S.D.), and in ampules, 99.42 +/- 0.44 were in good agreement with the labeled quantities (25 mg/lg gel, 100 mg/2 ml ampule). The recoveries were in the range of 98.65-100.63 and 99.1-101.5% for gels and ampules, respectively.