The effects of the neodymium-yttrium aluminum garnet (Nd-YAG) laser on several commonly used endotracheal tubes were examined. Six different types of tubes were tested for flammability. Three tubes were clear, transparent polyvinylchloride with black lettering on the surface. One was yellow–green silicone rubber with green lettering on the surface. One, which was opaque gray with no printing or marks on it, was designed specifically for use with the carbon dioxide (CO2) laser, and one was opaque red rubber with black letters printed on the surface. The latter was tested with and without a wrapping of reflective aluminum tape. On each tube a clear, unmarked area and an area with printing were tested. In each area the tube was impacted by the laser at three to five points. Pulsed and continuous patterns of laser impact were used. Power ranged from 20 to 50 W. The clear polyvinylchloride tubes were not damaged by a pulsed pattern of exposure in unmarked areas. Segments with black printing or marks were consistently damaged. Continuous laser exposure consistently damaged clear portions of the tube. In clear unmarked areas, silicone rubber tubes were damaged with the pulsed pattern when exposure reached 50 W for I s. Areas with green lettering were damaged at the lowest level of exposure. Continuous laser exposure at 30 W damaged clear portions of these tubes after 7 s. Opaque red rubber and opaque gray tubes were damaged at the lowest levels of exposure in both clear and marked areas with pulsed and continuous laser emission. A wrapping of reflective aluminum tape offered no protection. The study demonstrated that all the tubes tested are vulnerable to damage when exposed to the Nd-YAG laser. Transparent, unmarked polyvinylchloride is relatively resistant. Colored markings on clear tubes and colored opaque or semiopaque tubes absorb the light energy and are easily damaged. In contrast to CO2laser exposure the covering of red rubber tubes with reflective aluminum tape offers no protection.