Seven patients are described who had a distinctive syndrome of chest wall restriction caused by asbestos-induced pleural fibrosis. All had severe dyspnea and predominant pleural disease on radiographic examination, with pulmonary function findings of reduced vital capacity, total lung capacity (measured in five patients), and maximal voluntary ventilation. Five patients had ventilatory failure with carbon dioxide retention; four of these have died and one is close to death. Examination of the thoracic organs in five patients showed minimal or no parenchymal fibrosis in three and less severe involvement of the parenchyma than of the pleura in the remaining two. Neoplasms were suspected in three patients because of extension of the pleural fibrosis into the lung. Two of these patients had pleural uptake of 67-gallium citrate attributable to the inflammatory reaction. With the increasing duration since onset of exposure in the nine million workers who have been exposed to asbestos, as well as in other exposed persons, it is expected that additional cases of ventilatory failure caused by asbestos-induced pleural fibrosis will be encountered.