Bone marrow cells from most patients with acute promyelocytic leukemia contain a highly specific cytogenetic rearrangement, a reciprocal translocation between the long arms of chromosomes 15 and 17. Several cases of variant translocations involving 17q but not 15q have been reported, leading to the suggestion that the break in 17q rather than the one in 15q is the crucial change in the regular t(15;17). We describe a hematologically typical case of acute promyelocytic leukemia with a t(3;15)(q21;q22). This is the first report in this leukemia subset of a variant translocation affecting 15q without involvement of 17q.