BACKGROUND: Plasma cell balanitis or balanitis of Zoon (BZ) is a frequent diagnosis in mature men and lesions are generally localized on the glans but may involve the prepuce; its aetiology remains unknown. OBJECTIVES: To present our experience with tacrolimus 0.1% ointment in the treatment of two patients with BZ refractive to other topical treatments. PATIENTS AND METHODS: Two uncircumcised mature caucasian males were seen, both presenting with BZ; topical tacrolimus 0.1% ointment twice daily was prescribed in each case. RESULTS: Marked improvement of the lesions in both patients has been observed, with follow-up of 1 year and 10 months, respectively. CONCLUSIONS: Topical tacrolimus 0.1% ointment is an effective and safe treatment for BZ.