Pulmonary function in 25 patients with a severe degree of kyphoscoliosis was studied. Severe restrictive ventilatory insufficiency and hypoxaemic-hypercapnic respiratory failure were discovered. Isolated deformities of the vertebral column were diagnosed in 15 patients while ten patients, apart from diagnosed kyphoscoliosis, had associated chronic obstructive pulmonary diseases. Significant differences in pulmonary function impairment between these two groups, i.e. patients with associated chronic obstructive pulmonary disease, were observed. This indicates that associated pulmonary disease accelerates the development and course of respiratory failure. Respiratory blood gas analysis in 11 patients over the course of two years showed significant worsening of hypoxaemia and hypercapnia, which implies that in patients with kyphoscoliosis the disease has a rapid progression once the respiratory failure develops.