Photodynamic therapy after topical application of 5-aminolevulinic acid is an effective therapy for nonmelanoma epithelial skin cancers. It has also been used for some cases of cutaneous T-cell lymphoma. We treated 4 patients with different cutaneous T-cell lymphomas with photodynamic therapy. Those patients had previously reached a partial remission with more conventional therapies, but single lesions had remained. In all of these cases a complete remission of these lesions was achieved. We, therefore, suggest that photodynamic therapy can be a useful additional treatment modality for patients with therapy-resistant lesions of cutaneous T-cell lymphoma.