The presence of trypsin-like enzymes was evaluated in different waste fractions produced during mechanical peeling of Antarctic krill (Euphausia superba) using N-alpha-benzoylarginine p-nitroanilide as substrate. The enzymes were highly concentrated in the exudate (drip) obtained after thawing 25 kg of frozen krill blocks. They presented an unusually high stability in this material, retaining over 40% of the initial activity after 60 days of storage at 45 degrees C. From this wastewater, trypsin-like enzymes were purified 140-fold in one step by affinity chromatography on p-aminobenzamidine Sepharose 4B. The purified enzymes migrated as a broad band in polyacrylamide gel electrophoresis and presented a molecular weight between 32 000 and 33 000. The use of krill processing wastewater as a source for commercial production of trypsin-like enzymes is discussed.