Objective The evaluation of the effectiveness of topical photodynamic therapy with 5-aminolevulinic acid (5-ALA) and green laser light on superficial basal cell carcinomas. Background Topical photodynamic therapy with exogenous 5-ALA and visible or red laser light has been used up to now for the treatment of superficial non-melanoma skin tumors. Patients and methods Four patients with nine superficial carcinomas participated in this study. The tumors were irradiated with green laser light 5 h after the application of cold cream with 20% aminolevulinic acid under occlusive dressing. Results All nine lesions were resolved with a single treatment and clinical evidence of recurrence was observed in one tumor 1 year after the therapy. Conclusion Topical photodynamic therapy with exogenous 5-ALA and preen laser light is very effective for superficial basal cell carcinomas. (C) 1997 Elsevier Science B.V.