Background It is known that the incidence of skin cancer is rising rapidly worldwide, but no reliable figures on multiple nonmelanoma skin cancer (NMSC) are available. Aim To determine the actual incidence of skin cancer in dermatology practice and to estimate how this relates to the first primary tumours (registered at the Eindhoven Cancer Registry). Methods We examined 1001 randomly selected patient records at Catharina Hospital Eindhoven for mention of skin cancer. For each patient, skin cancers were recorded in a database, starting from 1 January 2004 until 1 March 2010. The time interval between tumours and any history of skin cancer were also recorded. Results Of this group, 876 patients were treated for skin cancer during the study period. We recorded a total of 2106 tumours with a mean of 2.4 skin cancers per patient. Nearly half (46%) of patients developed multiple tumours, and the second tumour developed within a median period of 5 months. Over a quarter (28%) of patients were known to have had skin cancer before 2004, the start of the study period. Conclusions The number of NMSCs in practice differs substantially from the number of first primary histologically confirmed NMSCs, as usually reported by the Eindhoven Cancer Registry. To obtain the optimum benefit from registration of NMSC, it is recommended to register all NMSCs, because only this complete number will give an insight into the incidence of the rising skin-cancer numbers. Because subsequent tumours occur frequently, NMSC should be regarded as a chronic disease, and innovations in disease management are required for cost-effective control. Click here for the corresponding questions to this CME article. © 2013 British Association of Dermatologists.