We have developed a DNA RFLP test to resolve paternity cases in which the accused man is included at a low probability of paternity by conventional testing. The DNA probe p79-2-23 was used to determine the allele frequency distribution for the locus D16S7 in the North American black, Caucasian, and Hispanic racial groups. Approximately 3,500 TaqI-digested DNAs were analyzed from the three populations studied. An apparent continuum of alleles was detected varying in size from 2.9 kb to 8.3 kb. Estimates of the average probability of exclusion were found to be .90 and .79 for the North American black and Caucasian populations, respectively. Gene frequency data for common and rare alleles indicated a potential paternity index ranging from 2 to 450.