Experiments with growing rats have been carried out to determine the specific changes in the biological value of finely minced meat following an increase in the total ratio of collagen from 6·1% to 21·2% of the total proteins. It has been established that within the above range the biological value and net protein utilization tended to drop, the difference being statistically insignificant. At the same time, an increase in the collagen content to 14·5% did not reduce the efficiency of tissue protein biosynthesis. It has been demonstrated that the above differences in the biological value for humans and rats are due to their varied requirements for protein composition. Therefore, the results obtained do not contradict the conclusion favouring a positive effect of a 15-20% increase in the total ratio of collagen on the efficiency of utilizing meat proteins for the human body's biosynthesis.