Diagnostic assessment of focal pleural mass requires CT examination, particularly in follow-up of anamnestic tumour conditions. Since 1976 well-delineated pleural masses that were suspicious for malignancy on chest films, were identified in 11 patients as lipomas, using CT. They showed semicircular, oval or polygonal shape, but no really "spheric" aspect on biplane chest films. Main diameters of these masses were 2.5 to 6 cm and only once 11 cm. Density values mostly ranged from -110 to -70 HE (min. -133, max. -22 HE) in nonenhanced CT studies. Findings were localised adjacent to the parietal pleura seven times (in one patient two separate findings) and to the diaphragmatic pleura five times. In 7751 CT examinations of the chest, the incidence of pleural lipomas was 0.14%, their prevalence concerning solid pleural lesions being 5.3%. Among all intrathoracic lipomas those in mediastinal and paracardial location respectively were definitely more often (30 patients).