The total serum amylase levels of patients with moderate and severe acidemia and of hospitalized control patients without acidemia are shown. The means for the groups with moderate and severe acidemia were significantly greater than the mean for blood donors and differed significantly from the mean for the 25 patients without acidemia. The mean total serum amylase level for the group with severe acidemia was also significantly greater than that for the 9 severely ill control patients without acidema. The mean for the group with moderate acidemia just missed statistical difference when compared with the mean for this same severly ill control group. Five of ten patients with a pH less than than 7.20 and 7 of 23 patients with a pH ranging from 7.20 to 7.31 had total serum amylase levels above the blood donor reference range. Of the 33 patients with acidemia, 5 had elevations of serum amylase greater than twice the upper limit of the blood donor reference range. Of the 12 patients with acidemia who had hyperamylasemia, 3 had metabolic, 2 had respiratory, and 7 had mixed metabolic-respiratory acidosis.