&NA;The effects of supplemental albumin infusion on serum protein homeostasis were studied in 94 seriously injured patients who received an average of 14.4 transfusions, 9.2 L electrolyte solution, and 829 ml fresh frozen plasma before and during operation. Based on randomization, 46 patients received an average of 31 gm albumin during operation followed by 150 gm/day for 5 days; 48 patients received no albumin. Supplemental albumin caused a significant (p=<0.05) increase in total serum protein and albumin concentrations. In contrast, supplemental albumin caused a significant decrease in &agr;1globulin, &agr;2globulin, &bgr; globulin, &ggr; globulin, and fibrinogen levels. The prothrombin time used as index of prothrombin concentration was significantly prolonged in albumin patients. These changes, not previously documented, need further evaluation to determine clinical significance.