The Dutch Cancer Society developed the 'KWF Kanker Risico Test' (Cancer Risk Test) to improve the information available to the Dutch population regarding cancer risk factors. This Internet test, based under licence on the American 'Your Disease Risk' test, informs users about risk factors for 12 common types of cancer. The test provides an estimate of individual risk of a specific type of cancer and gives specific lifestyle advice that could lower that risk. This paper describes the development of the test, how it works, and its strengths and limitations.