The occurrence and morphologic aspects of granulomatous pulmonary angiitis were evaluated in open lung biopsy specimens from 128 patients with sarcoidosis. All of the specimens showed parenchymal granulomas characteristic of sarcoidosis, and in 88(69%), granulomatous angiitis was seen. In the speclimens that exhibited granulomatous angiitis, venous involvement was mos common, seen in 92% of the cases. In 61% of these biopsy specimens, only venous involvement was seen; in 31%, both venous and arterial involvement was present. Only 8% of the positive specimens showed arterial lesions exclusively. The extent of angiitis was quantitated. Focal segmental elastic tissue destruction, partial or complete, was a common finding. No instances of aneurysm formation, endothelial erosion, or thrombosis were observed. Occlusive narrowing of small vessels was frequent. Bronchial blood vessels were not involved.