The biological effects of excimer lasers and safety associated with their use were discussed. Excimer lasers operate in the 193 to 351 nanometer (nm) wavelength range producing short pulses of high energy ultraviolet (UV) radiation. They have been used to ablate tissues and nonbiological material to a small depth. As excimer lasers produce radiation in wavelengths where mutagenic and carcinogenic effects have been reported from other optical (nonlaser) sources, it was important to determine whether these effects can occur in tissues irradiated with these lasers. Most of the energy in the laser beam was used to form fragments during the ablation process; therefore, minimizing heating and subsequent thermal damage to the surrounding material. This reduced temperature effect was quite useful medically, but from an occupational health standpoint, irradiation of the skin could occur without a worker being aware. Safety concerns associated with excimer laser radiation were discussed. Little was known about the effects caused by irradiation at wavelengths below 254nm. In-vitro studies investigating the effects of 193 and 248nm irradiation have shown that 248nm radiation is cytotoxic, and that the mutagenic potential of 248nm radiation was greater than 193nm radiation. Use of excimer lasers in the workplace requires skin and eye protection. Material scattering occurs during ablation, so the face and eyes require full protection. Some gases used to produce excimer lasers can cause problems, so special cabinets and material data sheets for these agents should be used.