Strong HLA associations were found in Southern Chinese patients with skin eruptions due to allopurinol. The positive associations were with AW33 (Pc = 1.7 × 10-5; relative risk [RR] = 15.0, 95% confidence limit 5.2–42.9) with B17/BW58 (Pc = 2.9 × 10-9; RR = 46.3, 95% confidence limit 10.3–209.2). The negative association was with A2 (Pc = 8.3 × 10-5, RR = 0).The findings suggested a genetic predisposition to cutaneous drug reactions.