Summary This is a retrospective review of our experience in the treatment of the cutaneous eruption of mycosis fungoides (MF) with a combination of topical nitrogen mustard (HN2) and photochemotherapy (PUVA). Our aims were to evaluate the efficacy of the combination in clearing the cutaneous eruption of MF, to establish whether the remissions thus achieved could be maintained by the use of HN2 alone, and to determine whether the combination with PUVA would inhibit the development of sensitization to HN2. The regimes employed were found to be an effective means of clearing the plaque lesions of MF. The use of PUVA, either started simultaneously or five to seven treatments prior to HN2, was not found to significantly inhibit the development of sensitization to topical nitrogen mustard. Nevertheless, topical desensitization in those who sensitized allowed the use of long-term HN2 in the great majority of patients. Once the cutaneous eruption had cleared, long-term therapy with HN2 alone was found to be a simple, convenient, and effective means of maintaining the patient in remission. It should not however be regarded as a curative regime, since relapse was common when maintenance therapy was discontinued.