A bioassay was made on male SPS Norway rats of the Wistar strain to study the biological value of PSE meat protein in a ten-day trial. Pork meat of m. longissimus dorsi was denoted as PSE meat on the basis of low pH1 values, colour and water content. Raw meat and thermally treated meat was used for feeding (thermal treatment: 75 degrees C for 60 min). The biological value of altered meat (thermally treated products), expressed on the basis of PER, NPU and LPU values, draws attention to the difference from the biological value of normal meat. However, no such a difference was recorded in PSE meat administered in raw condition.