The study was designed to investigate the effects of frozen storage on the proximate composition and chemical indices of pike (Esox lucius) stored for a period of six months at À20°C. During storage the moisture, protein and fatty acid contents decreased and the ash, total volatile basic nitrogen (TVB-N) and peroxide value (PV) content increased significantly (P < 0.05). In the fresh samples the moisture, total protein and total lipid contents were 77.61%, 19.21%, and 2.3% respectively. At the end of the storage time the abovementioned parameters were measured as 75.98%, 16.95%, 0.9%, respectively. TVB-N and PV contents changed from 1.30%, 6.27, 0.18 in fresh samples to 2.21%, 15.12 mg/100 g and 1.73 meq o 2 kg À1 after six months frozen storage, respectively. Thirty fatty acids were found in pike fillets, with a higher percentage in fresh fish of polyunsaturated fatty acids (51.14%), saturated fatty acids (22.94%) and mono unsaturated fatty acids (22.61%). The PUFAs decreased to 31.67% at the end of the storage time. Although some changes in quality and nutritional value were observed in the pike fillets during frozen storage, the changes were within the acceptable range.U.S.