The "Nevus doctor" is a dermatoscopy based computer decision support tool to assist general practitioners (GPs) in the classification of pigmented skin lesions (PSLs). The aim of the program "Nevus doctor" is to help GPs increase their diagnostic accuracy, in particular regarding the selection of suspicious PSLs that need biopsy or referral to specialist health care for further assessment. The aim of this study is to investigate the diagnostic performance of the decision support tool in a primary care setting in Norway. We hypothesize that the diagnostic accuracy of the computer program "Nevus doctor" is better than the performance of the GPs.