In this book, a Medical Diagnosis System (MDS) is aimed to solve various clinical problems by identifying the correct diagnosis will obtain the exact diagnosis of patient's diseases as quickly and possible less cost. Which, this human intelligence is not enough that determines the diagnosis simply lost to the primary diagnosis. So it needs to artificial intelligence supports the diagnosis of human intelligence to reduce the likelihood of error because the error may cause danger to the life of the patient and the system helps us. This is through the collection of data for each patient (medical history, symptoms, tests, etc.) The system can gain education and experience and through help physician consultants. This system is taught through a large number of files of patients.