Purification of lipase from Pseudomonas aeruginosa (from both a washed cell suspension and crude culture supernatant as the enzyme source) was performed utilizing affinity chromatography. Affinity chromatography was carried out using n-dodecylamine bound to Sepharose 4B. Chromatography of the concentrated crude culture supernatant resulted in a 65 to 95 fold purification with 5.8% recovery. Washed cells collected from a ten hour culture suspended in water also produced enzyme. Activity of the washed cell suspension supernatant was found to be 4.5 fold higher than the activity of the culture supernatant. A thirty percent recovery was obtained using the washed cell suspension supernatant. The washed cell suspension provides a cleaner preparation for use with the dodecylamine-agarose chromatography in purifying the enzyme.