ABSTRACT BLOOD meal has been reported to be a poor source of protein for poultry rations (Mussehl and Ackerson, 1931; Titus et al., 1936). Grau and Almquist (1944) showed that the serum and fibrin fractions of beef blood are of much better quality than the blood cell fractions in which isoleucine was the principal limiting amino acid. Squibb and Braham (1955) have found blood meal to be a satisfactory source of lysine in chick rations at levels of 2 to 4 percent. Block and Boiling (1951) have listed the lysine content of blood meal as approximately 8.8% of the protein. Since lysine is very easily destroyed or rendered unavailable by heat in processing protein material it was of interest to determine the availability for chicks and poults of lysine in blood dried by two different methods. EXPERIMENTAL PROCEDURE Two samples of vat-dried commercial blood meal which is commonly used for fertilizer . . .