Objective: Tolerability and safety of 0.1% tacrolimus ointment in treating nickel-induced allergic contact dermatitis (ACD) were evaluated. Methods: Patients allergic to nickel applied nickel patches to each upper inner aspect of the arm for 4 to 8 hours daily. Tacrolimus was applied to patch site on one arm and vehicle to patch site on the other, twice daily. Physician's Global Assessment, signs and symptoms of ACD, pruritus scores, and adverse events were evaluated. Results: After 8 weeks, dermatitis in 45% of patients was clear or almost clear (Physician's Global Assessment) with tacrolimus; and 1% with vehicle (P < .001). Significant results were achieved as early as day 8. Tacrolimus was superior in ACD signs and symptoms improvement and pruritus reduction (P < .001). Adverse events were similar between treatments. Limitations: This model, involving one agent, may not be generalizable for other agents. Conclusions: Tacrolimus ointment 0.1% is well tolerated and significantly more effective than vehicle in treating chronically exposed, nickel-induced ACD.