An assessment of early graft function in canine single lung transplant recipients was made by analysing early postoperative radiographic progression, lung perfusion, bronchial patency and bronchial anastomotic wound healing and histopathology of the allografted lung. Eighteen mongrel dogs weighing 15kg on average were used. Donor lung bloc with a generous atrial cuff, the pulmonary artery and left bronchus were taken and flushed with Euro-Collins solution which implanted in the pneumonectomized recipient dog. Anastomosis was done with the atrium, pulmonary artery and bronchus in that order. To assess an early graft function, a protocol for a grading system was designed into the chest roentgenogram, lung perfusion scan, bronchial patency and histopathologic progression of the bronchial anastomosis and allografted lung (Table 1). The results were obtained as follows: Radiographically, clear to infiltrate was seen in 67% (8/12), 33% (5/15), 30% (3/10) and 33% (2/6) on postoperative day 0, 1, 2 and 3 respectively. Lobar to total opacification was 33% (4/12), 67% (10/15), 70% (7/10) and 67% (4/6) on days 0 to 3 (Table 2). Perfusion scan showed normal to mild defect in 43% (3/7) and moderate to severe defect in 57% (4/7) on day 0 and 100% (5/5) on day 2 (Table 3). The bronchial anastomotic site showed patent to mild stenosis in 100% (8/8) on day 0 and mild stenosis in 2/2 on day 9 bronchofiberscopically, and showed normal wound healing in 38% (3/8), cellular infiltration in 38% (3/8) and infarction in 25% (2/8) up to day 9 postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)