Tomograms made in the oblique postenor projection at an angle of 55° with respect to the dorsal plane, have been compared with conventional posteroanterior cuts in 1,270 patients with various respiratory diseases. A further series of oblique tomograms were made in 1,490 patients. Oblique cuts, as compared with frontal or lateral views, displayed a clearer outline of the anatomic components of the hilum. The lung was visible up to the level of the first rib, whereas this area was blurred by the scapular muscles on lateral views. Furthermore, the 6th segment and the 2nd segment are not superimposed. The oblique tomograms proved to be superior in the demonstration and location of hilar enlarged lymph nodes, and have shown far better segmental location or parenchymal condensation or retraction, because of the identification of segmental arteries or of the great fissure.