Telepathology, introduced in 1986 by Weinstein, was not adopted in Japan because its image could not be transmitted by the National Television Standard Committee (NTSC) transmission. In 1990 a new system of Hi-Vision (HDTV) with 1125 lines, was implemented in Yamagata University and was highly evaluated. This success was followed by new developments both in NTSC and HDTV telepathology systems. Real-time HDTV images are transmitted via optical fiber cables for in-house hospital operations. Static HDTV and NTSC images are transferred via integrated services digital network (64 Kbit/s and 1.5 Mbit/s). Today telepathology networks are extending all over the country.