In 67 cases of pleura mesothelioma and in matched controls (cardiovascular disease) a retrospective in depth interview was carried out. In 72% of cases occupational exposure to asbestos was elucidated, whereas in matched controls only 18% had a positive exposure history. In 60% of cases with positive history there had been a rather intensive exposure, however often intermittent; duration of exposure often was over 10 yr, latent period over 30 yr. In individual cases a short duration of exposure and/or latent period was observed. A relationship with smoking history could not be confirmed. Some unexpected possibilities for occupational exposure were found. All 67 cases were reviewed by a panel of pathologists; in 66% the diagnosis could be confirmed; in the other cases the diagnosis was never fully rejected. It could be shown that histological confirmation of diagnosis is highly dependent on adequate supply of material, at least to be obtained through thoracotomy, pleurectomy, preferably through autopsy. The authors stress the methodological aspects of a restrospective study: absolute underreporting dependent on method of history taking, relative underreporting dependent on method of selection of controls. Prevalences as reported in literature cannot be taken at their face value because of pitfalls in study design.