A total of 632 adults with atopic dermatitis applied tacrolimus ointment (0.03% or 0.1%) or vehicle twice daily for up to 12 weeks in two randomized, double-blind studies. This report focuses on the efficacy of tacrolimus ointment in these studies. The mean percent body surface area (%BSA) affected at baseline was 45%, and 56% of patients had severe atopic dermatitis. Evaluations included a physician's global evaluation of clinical response, %BSA affected, individual signs of atopic dermatitis, the Eczema Area and Severity Index (EASI) score, and the patient's assessment of pruritus. A 90% or greater improvement from baseline in disease status was observed for 6.6%, 27.5%, and 36.8% of patients in the vehicle, 0.03% tacrolimus ointment, and 0.1% tacrolimus ointment groups, respectively (P<.001), and 50% or better improvement was observed for 19.8%, 61.6%, and 72.7% of patients, respectively. Tacrolimus ointment-treated patients showed significantly greater improvement than vehicle-treated patients for all efficacy parameters evaluated, including the %BSA affected, the total score and individual scores for signs of atopic dermatitis, the patient's assessment of pruritus, and EASI score. The 0.1% concentration was more effective than the 0.03% concentration, particularly in patients with severe disease and/or extensive BSA involvement at baseline and in African Americans. Tacrolimus ointment is an effective therapy for the treatment of adult patients with atopic dermatitis on all skin regions including the head and neck.