A population of 94 unrelated rhesus monkeys was typed for MLC antigens using 38 homozygous typing cells which define ten RhLA—D specificities. A genetic analysis showed that the ten D specificities are alleles of a single locus, the gene frequencies of which are in Hardy‐Weinberg equilibrium. The association between the cellularly defined D and the serologically defined DR antigens in the population was usually high, confirming the close relationship between D and DR antigens. Two new associations were found, i.e. between the D‐locus antigens 9 and 10 and the serologically defined B‐cell antigens 109 and 101, respectively. This observation confirms prior speculations that the latter two antigens may belong to the DR