From April 3, 1976, to Dec 31, 1979, one hundred thirteen fatalities were reported to the Food and Drug Administration as a sequela of the transfusion of blood or blood products. Thirty-three fatalities were due to posttransfusion hepatitis, and three involved plasmapheresis or leukopheresis donors. The remaining 77 cases were of three categories: 47 cases (61%) were due to "clerical errors" such as drawing the wrong blood specimen of giving the wrong unit of blood to the patient; eight cases consisted of genuine errors that occurred in the laboratory; and 22 cases were due to miscellaneous problems, most of which were unpreventable.