To obtain information about the occurrence of pleural mesothelioma on a population basis in Brazil, mortality related to pleural tumors in the State of Rio de Janeiro during 1979–2000 was examined. Death certificates with pleural tumors as the main cause of death and hospital records were analyzed, together with histopathologic material, which was reevaluated. Of 217 death certificates coded as pleural tumors, 34.1% were considered wrongly coded. Results after reclassification were: definite mesothelioma = 45 cases; probable = 7; possible = 31; inconclusive = 65; other tumors = 11. Thus, the number of mesotheliomas in Rio de Janeiro in 1979–2000 is estimated to have been 83. The analysis also suggests a problem with mortality codification in the State.