A retrospective analysis was made of all spontaneous pneumothoraces admitted to a Respiratory Unit between 1976 and 1981. There were 117 individuals responsible for 148 admissions, with a male to female ratio of 2: 1, giving a higher incidence amongst females than has been previously reported. Significantly fewer admissions were noted during May, June and July. Of the total survey population 89 per cent had smoked and in 40 per cent there was pre-existing lung disease. There was a history of two or more pneumothoraces in 36 per cent. Tetracycline pleurodesis, while attempted in 19 patients, was successful in only ten. Twelve patients underwent thoracotomy with a preponderance following right sided lesions. The duration of admission was more than 20 days for 17 per cent of the population. The aetiology, pathogenesis and management of pneumothorax is discussed.