In the 33-month period April 1985 to December 1987, endomyocardial biopsy was performed 314 times in 23 patients with orthotopic (21) or heterotopic (2) heart transplants at Baptist Medical Center. The technique is described. Adequate tissue was obtained in 99% of cases and there was only one complication from the procedure. Mild to severe acute rejection was seen in 105 specimens (33%). The histopathological interpretation has proved invaluable in the care of patients with heart transplants.