Syrian hamsters were fed one of three levels of lactalbumin (10, 20 or 40%) or a commercial diet from 4 weeks of age. The hamsters were mated at 12 weeks of age and parents (Fo generation) and offspring (F1 generation) remained for life on the assigned parental diet. Hamsters were killed to evaluate nutritional status from both generations at 4, 10, 22, 34 and 64 weeks of age. Remaining hamsters were allowed to live out their natural lifespan. Female hamsters generally grew faster with each increment in lactalbumin. Growth was greatest in male hamsters on the 20% lactalbumin diet and greater in the F1 than in the F0 generation. Reproduction was superior in hamsters fed the commerical diet and differed by season in those given purified diets, with the best performance following the autumn matings. Litter size and body weights of offspring at weaning increased from hamsters fed 10% of those fed higher levels. In the F0 generation, the longest female lifespans were observed in the 20 and 40% lactalbumin groups, respectively. The F1 generation females had longer survivals with each increase in lactalbumin. Male survival in both generations increased from the commercial diet to the 40 and 10% lactalbumin levels and was greatest in males fed 20% lactalbumin diet.