A multi-media magneto-optical disk filing system which stores the voice of image interpretation and order of image diagnosis issued at physicians departments has been developed. The advantages of these 5.25 in., 600 MB disks are rewritability and compactness; they are applicable to circulation media as well as filing media inside hospitals. In this paper, the status of magneto-optical disk (MOD) application to medical images involving standardization activity is briefly introduced. Results of system analysis of the hospital at Osaka University School of Medicine are presented, and the design of HIS/RIS/PACS and role of MOD through HIS/RIS/PACS are described. The result of the experiments -- oral reporting accommodation, together with medical images, interchangeability check, and hand carry acceptance check -- are also reported. Technology assessment steps and future development are further discussed in terms of speed, security, file integration, and operability.