This investigation assessed the cardiopulmonary performance, core body temperatures, and arterial blood gases of Hispaniolan Amazon parrots (Amazona ventralis) during 60 minutes of isoflurane anesthesia, using the Hallowell EMC Anesthesia WorkStation (AWS) in combination with controlled intermittent positive pressure ventilation (C-IPPV) or a nonrebreathing system (Bain circuit) with spontaneous ventilation (SV) (n = 6 birds/group). Direct arterial blood pressures, arterial blood gases, end-tidal carbon dioxide (ETco₂), end-tidal isoflurane concentration, heart rates, respiratory rates, and esophageal temperatures were monitored during a 60-minute period of isoflurane anesthesia. Compared with baseline measurements and SV, C-IPPV significantly decreased Paco₂ and increased pHa but did not significantly reduce mean arterial blood pressure. No significant difference in esophageal temperature was observed between the birds receiving C-IPPV and those breathing spontaneously on the Bain circuit. The PaCO₂-ETco₂ gradient was significantly greater in birds receiving SV compared with birds receiving C-IPPV. According to the measured parameters, there were neither deleterious effects nor any apparent advantages associated with positive pressure ventilation. The Hallowell EMC AWS appears to be safe and effective when anesthetizing small birds and will be particularly useful during anesthetic periods when positive pressure ventilation is indicated.