To explore the useness of fish oil (active EPA-cod liver oil) as a source of eicosapentaenoic acid (EPA, 20: Sn. 3), this study was performed on a total of 120 Fayoumi pullets which were randomly allocated into three equal groups (40/ group). The first group was fed on a basal control ration. It contained 3% cotton seed oil, which had high amounts of linoleic acid (18: 2n-6) and little amounts of n-3 polyunsaturated fatty acids. The other two groups were fed on a modified diet in which 50% and 100% of cotton seed oil was replaced by active EPA-cod liver oil (rich in omega-3 polyunsaturated fatty acids), respectively. The results showed that, addition of active EPA-cod liver oil particularly improved egg weight, egg mass production and feed conversion. However, the levels of plasma triacylglycerol, total cholesterol and low density lipoprotein were decreased. A significant increase (p < 0.01) in the three different omega-3 polyunsatureated fatty acids a-linolenic, (18:3 n-3), eicosapentaenoic, (EPA, 20:5 n-3) and docosahexaenoic, (DHA, 22:6 n-3) acids were observed in the liver and egg yolk of hens fed on fish oil for two months, the duration of the experiments.