In view of possible clinical use of the pulmonary homograft for right ventricular outflow tract reconstruction a comparative study with the aortic counterpart was performed. Samples of aortic and pulmonary walls from 10 cadaveric hearts were assessed for viability and morphologic characteristics before and after storage in nutrient-antibiotic solution. The viability, as evaluated by an autoradiographic technique, was similar in both aortic and pulmonary specimens at the time of dissection, after 2 weeks, and after 4 weeks of storage. The histologic examination showed no changes in the structure of the media in all samples up to 4 weeks of storage. The total calcium content per gram of tissue in the pulmonary media was on an average less than half of that in the aortic counterpart. We conclude that the pulmonary homograft is preserved the same as the aortic homograft and, accordingly, it becomes available for clinical application. Moreover, a lesser content of elastic tissue and a lower amount of total calcium may, in all likelihood, make the pulmonary wall less prone to calcification.