Tacrolimus ointment is a nonsteroidal topical immunomodulator that was formulated specifically for the treatment of atopic dermatitis. A total of 255 children, 2 to 15 years of age, with moderate to severe atopic dermatitis applied 0.1% tacrolimus ointment twice daily for up to 12 months to assess long-term safety and efficacy. Patients on average were treated with tacrolimus ointment for 279 days or 87% of study days. Substantial improvements in the signs and symptoms of atopic dermatitis, percent body surface area affected, and the patient's or parent's assessment of pruritus were observed during the first week of treatment and were maintained throughout the study. Transient skin burning and itching were the most common drug application site adverse events. Occurrence of these symptoms decreased after the first few days of treatment. There was no increased incidence of infections or other significant adverse events. Effectiveness of tacrolimus was maintained with prolonged daily use. Tacrolimus ointment (0.1%) is safe and effective for long-term treatment of atopic dermatitis in children.