For environmental and occupational safety reasons, the inhalation anesthetic isoflurane must be removed from indoor air in hospitals. The present work investigated experimentally the coadsorption of isoflurane and water on four different commercial adsorbents: two activated carbons and two zeolites. Adsorption isotherms from dry and humid atmosphere are shown and discussed, i.e., mixture data are compared with those of the pure substances. For all four adsorbents the dominant parameter regarding structural properties is the pore size distribution. In the case of the zeolites, the surface chemistry, especially the aluminum content, plays a role, too.