Imiquimod as a topical immune response modifier leads to a localized production of interferon and other cytokines. Apart from its use for genital warts it has therefore been used as treatment for different cutaneous neoplasms, including a few cases of cutaneous T-cell lymphoma. We treated 8 patients (4 with mycosis fungoides, 1 with CD30+ anaplastic large cell lymphoma and 3 with primary cutaneous B-cell lymphoma) with topical imiquimod. Therapy was started three times per week, in cases without response, the frequency was increased to a daily application. Two patients with mycosis fungoides and the patient with the CD30+ anaplastic large cell lymphoma had a complete clinical remission, the other two patients with mycosis fungoides did not show a response to imiquimod. Of the patients with cutaneous B-cell lymphoma, two reached a partial remission, one did not respond to therapy. Two patients had side effects such as erythema and pruritus which disappeared when the frequency of therapy was reduced. Our preliminary data show that imiquimod might be effective in some cases with therapy resistant lesions of cutaneous T-cell lymphoma as well as of cutaneous B-cell lymphoma, but more controlled studies are needed.