This study investigated the use of two anesthetic agents, isoflurane and carbon dioxide, in Chilean rose tarantulas (Grammostola rosea). We compared the onset, duration of anesthesia, and recovery time with both gases, and made observations regarding the effects of the anesthetic protocols. Subjectively, episodes for the isoflurane animals were uneventful. The spiders were calm throughout and did not respond adversely to gas exposure. Conversely, animals anesthetized with carbon dioxide experienced violent inductions and recoveries; the tarantulas appeared agitated when the carbon dioxide flow began. Seizure-like activity and defecation would frequently be noted prior to induction with carbon dioxide. Neither isoflurane nor carbon dioxide seemed to have any clinically apparent short- or long-term impact. The animals were all normal for at least 1-year postexperiment. Future studies should focus on defining the impact, if any, that these anesthetic agents have on the health of invertebrate species. Zoo Biol. 32:101-103, 2013. © 2012 Wiley Periodicals, Inc.