The effects of formulation variables of topical lotion on the skin permeation of ketoprofen were evaluated using excised rat skins. The formulation variables were the amounts of poloxamer 407, drug and ethanol, and penetration enhancers. The Keshary-Chien diffusion cells were used for the diffusion study. The flux of ketoprofen linearly decreased as the concentration of poloxamer increased from 5% to 15% in the preparation, and linearly increased as the amount of drug increased. Penetration enhancers such as fatty acids and fatty alcohols showed markedly enhancing effects at the level of 5%. Among them, the highest flux was shown in linolenic acid. From these results, optimum formula containing 3% ketoprofen, 5% poloxamer 407, 40% ethanol and 5% linolenic acid having the flux of 537.6 $mu$g/$ extrm{cm}^2$/hr were noted.