Expert systems are systems that use recorded human knowledge in computers to solve problems that usually require human expertise (Turban, 2005). Skin disease diagnosis expert system is an expert system that is designed as a tool to diagnose skin diseases in humans caused by a fungal infection. This expert system developed to provide information about the diagnosis of skin diseases due to fungal infections in humans and how its management, and can produce a quick alternative solution in determining the type of fungal infection of skin diseases by looking at the symptoms without having to consult with an expert. The expert system is built using the PHP programming language and MySQL as its database and uses backward chaining method for making conclusions