A protease inhibitor from fish eggs was fractionated using chromatographic methods. The fractionation efficiency was evaluated in terms of specific inhibitory activity (SIA, U/mg), purity (fold), total inhibitory activity (TIA, U), and recovery (%). The protease inhibitor (PI) from egg extracts of skipjack tuna (ST Katsuwonus pelamis), yellowfin tuna (YT Thunnus albacares) and Alaska pollock (AP Theragra chalcogramma) was fractionated using Sephadex G-50 gel filtration and DEAE-Sepharose CL-6B anion exchange chromatography based on protein size exclusion and net charge, respectively. Fractions exhibiting strong inhibitory activity were contained in the 30-50 kDa fraction on gel filtration and in the range of 0.4-0.7 M NaCl gradient fraction on anion exchange chromatography. The respective TIA and percent recovery of the fraction obtained with gel filtration toward trypsin and $N{alpha}$-benzoyl-L-arginine-p-nitroanilide (BAPNA) were 2,758.7 U and 29.6% for ST, 1,005.5 U and 25.6% for YT, and 1,267.5 U and 26.0% for AP. Gel filtration chromatography was more effective at fractionating PI than using ion exchange chromatography. These results suggest that fish eggs act as serine protease inhibitors and might be useful for protease inhibition in foodstuffs.