Summary: Four inbred lines of SCWL chickens were assayed for the response to a single intravenous injection of bovine serum albumin. Quantitative antibody nitrogen determinations of the sera obtained on day 8 postinjection show that differences do exist among lines in the ability to respond. Chickens not responding to a single injection of antigen, did respond to a second injection. No nonresponders were found in any of the lines tested. Chickens assayed for circulating antibovine serum albumin on days 6, 8 and 10 showed the antibody content to be higher on day 8 than on day 6 or 10 postinjection. No exception was found in 133 birds tested. No reduction in variability was immediately apparent in using these inbred lines rather than chickens from a randomly bred population.