An on-line, real-time system for recording transfusion service activities was added to an existing LABCOM general laboratory computing system. The new programs monitor the blood inventory, crossmatches performed, units issued and final dispostion of all units of blood. The computer prints the final patient record of units crossmatched and transfused, generates the patient bill, and tallies the workload. The system has reduced the manual clerical operations from 12 to 14 man-h per day to 8 or less. Acceptance by the medical technologists has been excellent.