A reliability study of the Brigance Comprehensive Inventory of Basic Skills (CIBS) is presented. All test-data collectors were provided onsite training in the administration and scoring of the CIBS. The sample included 85 black and 319 white students from grades two through eight, from parochial and private schools, in a southeastern metropolitan area. Test-retest reliability coefficients were computed for Forms A and B for the total group, by race, and by sex. For the sample divided by race and by sex, the coefficients ranged from .65 to .91. There were negligible differences in reliability according to sex, and only small differences according to race. Alternate forms reliability coefficients compared favorably with the reference value of .88. The component of the CIBS that was consistently least reliable was Listening Vocabulary: reliability coefficients were less than .7 for the group as a whole and for the group split by sex and split by race. Poor performance at a few grade levels also negatively affected Reading Vocabulary. It was concluded that the reliability of the CIBS is acceptable. (PN)