Actinic keratosis on sun-damaged skin are very common in individuals with fair complexion. Management encompasses cryosurgery, tretinoin or 5-fluorouracil-cream. Bowen's disease, however, requires surgical excision or radiotherapy. Basal cell carcinoma and squamous cell carcinoma are the two most common malignant skin tumours in Western Europe. Typically these tumours can be managed either by excision and primary wound closure, by cryosurgery or by radiotherapy. The method of choice is determined by the type and location of the tumour and the general condition of the patient. For more difficult-to-treat malignant skin tumours surgical resection with histological margin control is required. Mohs' micrographic surgery is a specialized procedure. This method entails to a full work-up of the excisional margins. The defect is closed only after histological verification of tumour-free surgical margins. Difficult-to-treat tumours are recurrent, sclerodermiform and large (diameter more than 20 mm) basal cell carcinomas. Indications for margin control in squamous cell carcinomas are tumours with more than 20 mm of diameter, with more than 5 mm thickness and with poor histologic differentiation (Broders grade III and IV, desmoplastic squamous cell carcinoma). Therefore, a skin biopsy is often required to plan the optimal treatment of a malignant skin tumour. The collaboration of primary care providers and specialists is beneficial in the management of difficult skin tumours. Renal transplant recipients under immunosuppression are prone to have squamous cell carcinoma of a more aggressive type. Dermatofibrosarcoma protuberans is another good indication for Mohs' micrographic surgery. A regular follow-up for recurrences or secondary tumours, as well as an effective secondary prevention of sun damage are important for skin cancer patients.