The purpose of the work is presentation of own experience in the use of thoracoscopy in patients with pathological pleural changes. In the years 1989-1991 in the Chair and Department of Pulmonology and Tuberculosis, Medical Academy in Gdańsk, 20 thoracoscopies were performed with simultaneous taking of material for histopathological examination. In 15 patients from this group the diagnosis was made confirming the aetiology of pleural pathological changes. It should be stressed that in the group of patients with suspected malignancy, the diagnosis was confirmed in 100% of cases. Thoracoscopy is a useful diagnostic procedure during which aimed pleural biopsy may be performed.