Relationship between stature and roentgenologically determined lung sizes was examined in 48 patients (mean age = 24.6 ± 6.2 years) with spontaneous pneumothorax, 46 male patients (mean age = 24.6 ± 3.8 years) with various diseases not related to the cardiopulmonary system, and 48 healthy male students (mean age = 24.3 ± 2.2 years). Patients with spontaneous pneumothorax were slender compared to the control groups but the body height was not different. The patients had significantly longer lungs than the controls, although width and depth of the lungs were similar between the three groups. Mean differences for the lung height between patients and healthy students were so small (mean = 1.2–1.7 cm, which is equivalent to 0.3–0.7 cm H2O) that stress alone does not appear to be a major contributor to the pathogenesis of spontaneous pneumo