Bronchoalveolar lavage fluid was collected from 12 anesthetized cats by use of an endotracheal tube and syringe adapter. The safety of the technique was evaluated by monitoring mucous membrane color, capillary refill time, pulse rate, respiratory rate, ECG, and arterial blood gas tensions and by necropsy findings. Group A consisted of 3 cats that were administered (by lavage) 4 aliquots of 20 ml of saline solution during anesthesia for placement of femoral artery catheters. Group B consisted of 4 cats that were administered a smaller total volume of saline solution (3 aliquots of 5 ml/kg of body weight) during a separate anesthetic period, other than the one for placement of catheters. Group C consisted of 5 cats administered 3 aliquots (5 ml/kg) of saline solution during a separate anesthetic period and administered supplemental oxygen for 5 to 10 minutes before and for 20 minutes after the lavage procedure. Group-A cats had a prolonged recovery period that was attributed to the lengthy anesthetic period required for placement of femoral catheters. The effect was eliminated in the cats of the other groups in which the lavage procedure itself accounted for only 5 to 10 minutes of anesthetic time. Evaluation of mucous membrane color, capillary refill time, ECG, pulse, and respiratory rate revealed no persistent abnormalities. Transient increase in pulse and respiratory rate was seen in some cats. Blood gas analysis revealed noticeable decrease in arterial oxygen pressures (PaO2) after the lavage procedure. In group-C cats, oxygen supplementation allowed the maintenance of normal or above normal PaO2. When oxygen was discontinued at 20 minutes, PaO2 was maintained at greater than or equal to 60 mm of Hg. The variability in oxygen pressures did not appear to correlate with the volume of fluid remaining in the lungs. Histologic evaluation of the lungs revealed no changes attributable to the lavage procedure. Most cats had minimal to mild inflammatory changes, and 4 cats had moderate to moderately severe bronchopneumonia. These changes were reflected in the bronchoalveolar lavage fluid, indicating that they were present at the time of lavage.