osteoporosis is a condition where bones porous without changing the shape or structure of the outer bones, yet the inside part perforated and more likely to fracture. a lot of people do not know the early symptoms osteoporosis. this research aims to design and create an expert system to diagnose osteoporosis by applyi naive bayes method. this method is used to establish parameter estimation by combining information from the sample and the other previously available information. this system using naive bayes method can clarifies the existence of osteoporosis