Gastric ulcer is a common chronic disease in human digestive system. Massive alcohol drinking can lead to gastric ulcer. In the present study we investigated the gastroprotective effect and the molecular mechanisms of Omega 3 polyunsaturated fatty acids(ώ-3 PUFAs)  in a rat model of ethanol-induced gastric ulcer.42 male rats were divided into six equal groups. Group 1 :( Control normal group) rats received no drugs. Group 2 :( Omega-3 group): rats receivedOmega-3 orally(244.8 mg/kg b.wt/day) for 14 days. Group 3 :( early ulcer group):rats received absolute Ethanol (0.5ml/rat) orallyand sacrificed one hour later after ethanol administration Group 4: (Early ulcer + Omega-3 protected group) rats received  omega-3 similar to group 2 for 14 days prior to absolute ethanol administration, then sacrificed after one hour. Group5: (late ulcer group) rats received absolute ethanol similar to group 3 and sacrificed  after 14 days. Group6:( Late ulcer + Omega-3 treated group)rats first administered with absolute ethanol then after one hour omega-3 was administered for 14 days. The results showed significant increase in No,L-MDA,GSH with marked decrease in CAT activity in stomachof ethanol- induced gastric ulcer in rats as compared with control normal group.However, a significant depletion of gastric tissue No, L-MDA  and GSH concentrations and marked increase in CAT activity were observed after omega-3 treatment compared to  ulcerated untreated rats. The qPCR results revealed a significant up-regulation of mRNA gene expression levels of TNF-a, MOP and iNOS in stomach of ethanol-induced gastric ulcer in rats. This expression was significantly down-regulatedafter administration of omega 3.Conclusively, omega-3 protects rat gastric mucosa against ethanol-induced gastric ulcer via anti-inflammatory and anti-oxidative mechanisms.