Wireless LANs using radio waves have recently gained popularity for installation in hospitals. Because electromagnetic waves transmitted from mobile telephones have been shown to cause interference with medical electronic equipment, prudence would seem necessary when introducing radio wave communication devices into hospitals. Therefore, we tested the effect of wireless LAN communication on medical electronic equipment and the effect of electronic equipment on wireless LAN communication. We observed nine pieces of electronic equipment in the operating mode while transmitting radio waves from a wireless LAN. Even when the access point was put very close to the medical electronic equipment surface and data was transmitted, no malfunction of the equipment was observed. The medical electronic equipment caused little change in the effectiveness of the communication device, although radio waves emitted from electric knives and a remote patient monitor reduced the reception rate to about 60%. The communication speed of the wireless LAN was temporarily reduced only when a microwave oven was located close to and facing the access point. Because output in Japan is limited to a maximum of 10 mW, wireless LAN following the IEEE802.11b standard should be able to be installed safely in Japanese hospitals. However, wireless LAN access points should not be installed near microwave ovens.