The ranges and means of certain morphometric indices of L. niloticus and the significance of variation of such indices according to the total length were studied. Morphometric characters reliable for taxo nomic purposes were determined according to the significance of the Y-intercepts of regression lines of some morphometric measure ments. the meristics studied included counts of the total vertebrae, abdominal and caudal vertebrae, gill rakers on the first right gill arch, lateral line scales, scales above and below the lateral line, scales around the caudal peduncle and soft rays of the dorsal, anal, pectoral and pelvic fins. A curvilinear relationship was found between the number of gill rakers on the first right gill arch and the total length of the fish.