We examined retrospectively the use of hydroxychloroquine in 9 patients with childhood dermatomyositis (DM). These patients had an incomplete response to corticosteroid therapy or had disease exacerbation when attempting to taper corticosteroids. They received hydroxychloroquine in a mean dosage of 3.6 mg/kg (range 2-5 mg/kg) while maintaining corticosteroid therapy. Significant improvement was noted at 3 months of therapy in rash (p less than 0.0001), proximal (p = 0.0004) and abdominal muscle strength (p = 0.0001) and at 6 months of therapy in reduced prednisone dosage (p less than 0.02). These data suggest hydroxychloroquine may be helpful in some patients with childhood DM, particularly those with prominent cutaneous disease or significant corticosteroid toxicity.