There is provided a medical information processing system including a diagnosis information storing section that stores thereon frequency information in association with an initial diagnosis and a conclusive diagnosis, where the frequency information indicates a frequency with which a combination of the initial diagnosis and the conclusive diagnosis that is different from the initial diagnosis is observed, a diagnosis receiving section that receives a diagnosis during a diagnosis process, and a disease information presenting section that presents, to a diagnosis-making person, one of the conclusive diagnosis and the initial diagnosis which is stored on the diagnosis information storing section in association with one of the initial diagnosis and the conclusive diagnosis which is the same as the diagnosis received by the diagnosis receiving section, in a manner according to the frequency information stored on the diagnosis information storing section in association with the initial diagnosis and the conclusive diagnosis.