Cardiopulmonary effects and the utility of a butorphanol/xylazine/ketamine combination were evaluated during twenty immobilizations of sixteen Baird's tapirs (Tapirus bairdii) between March 1996 and January of 1998 in Corcovado National Park (Costa Rica). The animals were attracted to a bait site and darted from tree platforms. The tapirs were estimated to weigh between 200 to 300 kg. Actual weights of three tapirs taken at later dates fell within the estimated range. A butorphanol, 48 +/- 1.84 ((x) over bar +/- SE) mg/animal IM, and xylazine, 101 +/- 2.72 mg/animal IM, combination was used to immobilize the animals. In some instances, ketamine was used either IM or IV at 187 +/- 40.86 mg/animal to prolong the immobilization period in addition to the butorphanol/xylazine combination. Naltrexone was used IM to reverse butorphanol at 257 +/- 16.19 mg/animal. Either yohimbine, 34 +/- 0.61 or tolazoline at 12 +/- 10.27 mg/animal, was used to reverse xylazine. The mean time from dart impact to first visible effect was 4.63 +/- 0.50 min ((x) over bar +/- SE). Mean time to sternal recumbency was 12.21 +/- 1.08 min. Mean time the tapirs were immobilized nas 45.63 +/- 3.6 min. Mean time to return to sternal recumbency and standing in animals that received yohimbine and naltrexone was 3.16 +/- 1.06 and 5.33 +/- 1.45 min, respectively Mean time to return to sternal recumbency and standing in animals that received tolazoline and naltrexone was 1.57 +/- 0.39 and 3.14 +/- 0.51 min, respectively Cardiopulmonary parameters including heart rate, respiratory rate, body temperature, electrocardiogram, percent oxygen saturation, and indirect blood pressure were recorded. Arterial blood gas analysis was performed on four animals. A mild degree of hypoxemia was evidenced by low arterial oxygen saturations. Five of 14 (36%) animals measured had oxygen saturations below 90%. Bradycardia (heart rates <45 BPM) was an expected finding in 11 (55%) immobilizations. Induction, recovery and muscle relaxation of each immobilization was graded. Premature arousal, which occurred in six (30%) animals, was the only problem associated with the immobilizations. Butorphanol/zylazine is a recommended protocol for immobilization of calm, free-ranging tapirs lasting less than 30 min. Supplemental intravenous administration of ketamine is recommended for longer procedures. Nasal insufflation of oxygen is recommended.