[en] Acanthosis nigricans in obese adolescents is frequently associated with hyperinsulinemia and insulin resistance. We report three cases of this condition. In the early stage the skin lesions appeared to be erythematous and pruritic, mimicking an inflammatory dermatitis. Dietary control and oral metformin hydrochloride markedly improved the lesions. Topical calcipotriol may also help to control the skin condition.