Summary Background: The objective of our study was to determine therapeutic response to photodynamic therapy (PDT) and adverse reaction of PDT in 126 patients with 141 lesions: 36 patients with 41 lesions of superficial basal cell carcinoma (BCC), 35 patients with nodular BCC, 42 patients with ulcerated BCC, four patients with 14 lesions of actinic keratoses, five with superficial squamous cell carcinoma (SCC) and four with Bowen's disease. Methods: Patients with skin malignancies were treated using 20% aminolevulinic acid (ALA) (Medac GmbH, Wedel, Germany) topically and light from an argon-pumped dye laser. Results: A complete response was achieved in 81.5% treated lesions. A partial response after PDT in 10.6% treated lesions, no response in 7.8% treated lesions and 11.3% lesions recurrences during 10–36 months follow-up were observed. Following light exposure skin lesions became necrotic and showed hemorrhagic crusts and the cosmetic outcome was excellent or good in 97 of the completely responding lesions (84.3%). Conclusions: Clinical studies reported by other groups have shown similar high percentages of clinical cure. PDT appears to be a more feasible alternative to conventional therapy of skin malignancies.