Photodynamic therapy (PDT) involving the sequential administration of photosensitizing drugs and light has a successful record in the treatment of superficial tumors. Recent investigations document not only cytotoxicity but also immunomodulatory effects of PDT. Cell type as well as state of activation and differentiation are among the parameters influencing susceptibility to PDT, thus allowing targeting of selected cell (sub-)populations. In addition to lasers, non-coherent light sources are also effective. These features, along with current clinical experience, suggest PDT as an interesting alternative to better established photochemotherapies in the treatment of widespread malignant and benign dermatoses.