The studies were carried out on 100 right lungs taken from dead human bodies of both sexes whose age varied from 16 to 81 years. The pulmonary artery and the bronchus were injected with a 65% solution of duracryl and then digested in sulfuric acid. The specimens obtained were then examined to determine the number and dimensions of the branches of the basal portion of the right pulmonary artery (RPA) penetrating into the basal segments of the right lower pulmonary lobe. Their length was 52 mm at the most, and their diameter 14 mm. Three types of ramification of the basal portion of the RPA were distinguished on the basis of the trunks, segmental and subsegmental branches present. In 72% of the cases the branches penetrating into the basal segments showed a tree-like type, in 2% of the cases a bushy-like type and in 26% of the cases a middle type.