Acid-base and arterial oxygen pressure (Po2) determinations were performed upon groups of rabbits with (1) fat embolism, (2) fat embolism plus hemorrhagic shock, and (3) hemorrhagic shock alone. The data suggest that the initial severe metabolic acidosis observed with fat embolism plus shock is principally a reflection of hypovolemia, and that the fat embolism per se contributes little to the acid-base derangements. Transient cyanosis with hypoxia was observed seven minutes following fat embolism, but this reverted by 30 minutes after embolization. In the group which received fat embolism plus shock, the mean 30 minute Po2 was actually slightly higher than the comparable preembolism value.