The suitability of Excimer laser beam for microneurosurgery was investigated in an animal experimental study. Cranial bones, cortex and the nervus ischiadicus of the rat were irradiated with 193 nm argon fluoride, 248 nm krypton fluoride, 308 nm xenon chloride and 351 nm xenon fluoride. After survival times of up to 30 days microscopic and electron optic findings of laser lesions at the tissues mentioned above, were studied. By means of the Excimer laser beam high precision tissue effects without or with only low thermal damage to the surrounding tissue were produced with any desired depth of penetration or extension. In analogy with the experiences gathered from animal experiments, a possible use is discussed for the removal of bone tissue around cranial nerves or vascular structures, of epileptogenic foci, or for cutting off pathways in pain surgery (e.g. the zone of entry of the dorsal root of spinal nerves).