Growth performance and proximate body composition of Oreochromis niloticus strains from different Lakes of Ethiopia were evaluated to determine the effect of strain variation on growth and body composition and further select the best performing strain for aquaculture development. Fingerlings of average weight 4.4 g were stocked at a stocking density of 20 fish/m3 in tanks (1.2 m3 each) in three treatments with four replicates each. Treatment groups were fed formulated feed with 30% crude protein at a rate of 5% body weight per day. Length and weight measurements were taken on monthly basis. Nutrient content was chemically determined following the procedure of Association of Official Analytical Chemists at the end of the experiment. Growth performance parameters, feed conversion ratio, body proximate composition (except carbohydrate) and survival rate were not significantly different (p>0.05) among the strains tested (Table 1 and 2). Generally, based on the current finding, strains of O. niloticus either from Lake Chamo, Babogaya or Hashengie can be used for stoking activities and further experiment, with further researches recommended to be conducted in this regard with more strains included.