This study was designed to compare the Biological effects of the cereals and legumes Proteins on albino rats. Fifty weaning albino rats weighing $49;gr{pm}2$ in both sexes were divided into 5 groups and fed corn crude protein diet, wheat crude protein diet, soybean protein diet, yeast diet and 30% sugar-casein diet for the control group. The protein contains same levels with isocaloric values each diet. After 12 weeks the rats were sacrificed for chemical analysis and the results are as follow ; 1. The highest food consumption was found in the groups of yeast and soybean, and the lowest was found in the groups of wheat diet and corn diet. 2. The groups of yeast & soybean protein showed the highest body weight increase, while the groups of wheat diet and corn diet showed the lowest. 3. Highly significant difference was found between the standard group and the groups of corn protein and soybean protein in Food Efficiency Ratio. (F. E. R.) (p<0.01). 4. Protein Efficiency Ratio showed a similar pattern as the F.E.R., however, there was no significant differences among the groups. 5. The kind of diets did not influence the hematology of the subjects. 6. The rate of nitrogen retention of male standard group was lower compared with all the experimental groups (p<0.01), and that of female soybean group was higher than any other groups (p<0.01). 7. Female corn diet group had the lowest organ weights, as found in the growth rate, which was significant (p<0.01). In the male corn diet group only the kidney showed significantly low in weight (p<0.01), and the spleen of male yeast group was also shown low with significance (p<0.01). 8. Nitrogen retentions of the liver and muscle in male corn diet group were lower than any other groups (p<0.05), and the brain nitrogen content of female standard group was high with significance (p<0.01). According to the results above, yeast and soybean protein can be regarded as a nutritious and also inexpensive protein sources.