Secondary spontaneous pneumothorax (SP) is an indication for thoracoscopic exploration and treatment just like primary SP. The same guidelines apply to both. During the last 12 years a total of 243 patients with SP were admitted to our Department of Pneumology; of these, 156 = 62.2% were treated by thoracoscopy. We employed an operation method described by Youmans et al. that we modified for thoracoscopy, namely, pleural abrasion. The relative number of thoracoscopies rose during 1975-1980 from 47% of all SP to 75% during 1981-1986. The relapse quota was 5.4% (total value); of the operated patients, only 3 suffered a relapse (1.2%). Since our department is the only one for diseases of the lung for a total population of 537,000, we can assume that these relapse rates can be-if at all-only slightly falsified by referrals to hospitals located in other Federal Lands.