The accessibility of the skin to light treatment, as well as the developments made by dermatologists in photodynamic therapy (PDT), creates an exciting apportunity to include it as a part of our standard therapeutic armamentarium. We report a 63-year-old man with an in situ squamous cell carcinoma located on a chronic radiodermitis area in a finger, treated successfully with PDT. PDT appears to be a viable alternative to conventional therapy for in situ squamous cell carcinoma as well as for other superficial tumours of the skin.