Abstract: Effects of four different molecular fractions of cod protein hydrolytic peptides( CPHP) on LPS- induced release of inflammatory cytokines were compared. CPHP was a whole mixture of cod protein hydrolytic peptides hydrolyzed by complex protease. The peptides were further fractionated by ultrafiltration into three fractions of CPHP1( > 5000 u),CPHP2( < 3000 u) and CPHP3( 3000 ~ 5000 u). Griess assay and ELISA kits were used to measure the levels of NO and inflammatory cytokines( TNF-α,IL-1β and IL-6),respectively. The results showed that the all CPHP fractions protected RAW264.7 cells from LPS( 500 μg / m L) induced cell growth inhibition,in a dose dependent manner,and protective effects of CPHP and CPHP1 were higher than that of CPHP2 and CPHP3. All CPHP fractions inhibited release of NO,IL-1β,IL-6 and TNF-α from RAW264.7 cells induced by LPS( 1 μg / m L),in a dose dependent manner.The inhibitory effects of CPHP and CPHP1 were higher than that of CPHP2 and CPHP3.In conclusion,all four fractions of CPHP had protective effect against LPS induced cell growth inhibition and release of inflammatory cytokines.The CPHP and CPHP1 had higher activity than that of CPHP2 and CPHP3.