Development of computer technology is very rapid effects on human life, not least in the world ealth. Application of expert system in the website and mobile with JSP and J2ME is one manifestation of the development of these technologies. This final project built an expert system that can diagnose and provide therapy in diabetes Nephropathy and completed with a confidence alue of the diagnosis. Confidence value is obtained by using method called certainty factor. Certainty factor is a method used in MYCIN in the mid of 1970, in anticipation of knowledge is usually incomplete and uncertain. By providing accurate knowledge based on nowledge and followed by test conducted which is done seriously, it is expected that this system can help to make diagnosis and provide therapy of diabetes mellitus correctly and accurately. Keywords: Expert System, Certainty factor, Diabetes Nephropathy, JSP, J2ME
