We have analyzed hematology data from 504 Individual male C57BL/6 x DBA/2 (hereafter called B6D2F1) mice. Clinical chemistry data from an additional 304 individual male B6D2F1mice have also been analyzed. The mice had served as drug-diluent controls in 24 toxicological evaluations of anticancer drugs administered singly or in combination. The studies were carried out under standardized conditions during an 18-month period between July 1975 and December 1976. Test values corresponding to 9 percentiles have been selected from an ordered ranking of values for each of 18 hematologic tests and 18 clinical chemistry tests. Since 95% of the values for a given test are found between the 2.5th and 97.5th percentiles, test values corresponding to these percentiles provide reference values (“normal” values) for these mice. The other percentiles (5th, 10th, 25th, 50th, 75th, 90th, and 95th) indicate the distribution of values between the reference limits for each test. Since values for all tests do not conform to the Gaussian distribution, this nonparametric analysis provides reference values that are more accurate than might be obtained from calculation of the mean and standard deviation of a given test. The B6D2F1mouse, commonly referred to as BDF1has been widely used for preclinical evaluation of anticancer drugs, and these data should be useful to investigators who are conducting qualitative and quantitative toxicity evaluations in these mice. © 1978, American Association for Cancer Research. All rights reserved.