Prostate cancer is cancer that develops in the prostate gland in the male reproductive system. This can occur if prostate cells multiply out of control. This disease is very widespread throughout the world. In the early stages, there are no clinical symptoms. To anticipate, all men are required routinely in checking the condition of each body through the symptoms that allow prostate cancer. However, to consult and examine with a doctor or an expert took a long time in waiting for the patient queue. Therefore, we need a system that can help men to examine and treat the disease. This research discusses the creation of an expert system to diagnose prostate cancer with a web-based forward chaining method. Data collection on symptoms, diseases also solutions are done in the early stages of making this expert system. This system is made using the PHP programming language and database namely MySQL. In this web-based diagnostic system is equipped with information such as understanding disease, symptoms, and treatment of diseases. The implementation results show that the expert system of prostate cancer diagnosis using web-based forward chaining method can work well on the website