A prospective cineradiographic and manometric study of pharyngeal and esophageal dysfunction was performed in 54 patients with rigidly defined scleroderma, poly-myositis, systemic lupus erythematosus, and rheumatoid arthritis. Decreased or absent distal esophageal peristalsis was demonstrated by cineradiography and manometry in 55 and 73 per cent of 22 patients with scleroderma and 13 and 3 per cent of 32 patients with other collagen diseases. This finding showed a highly significant (p <0.001 manometry and p <0.01 cineradiography) correlation with clinically diagnosed scleroderma. This manometric abnormality was seen less frequently (1 of 8) in patients with Raynaud's phenomenon unrelated to scleroderma. This difference was statistically significant (p <0.02).When clearly defined criteria for the diagnosis of the skeletal muscle dysfunction of polymyositis were used, no false positive diagnoses were made and, of the ten polymyositis patients, only two were diagnosed by manometry and one by cineradiography as having this disease. This study thus demonstrated that (1) distal esophageal smooth muscle dysfunction was relatively specific for clinical scleroderma; (2) significant pharyngeal and esophageal skeletal muscle dysfunction was an infrequent finding limited to polymyositis; and (3) manometry was somewhat more accurate and specific than cineradiography in diagnosing these changes.