In 1980 a prospective exposed/non-exposed cohort study was initiated in France by the Institut National de la Santé et de la Recherche Médicale (INSERM U 287) to evaluate the association between mortality and cancer morbidity and occupational exposure to vinyl chloride monomer (VCM). Eleven hundred VCM exposed subjects and 1100 VCM non-exposed controls matched for age (+/- 2 years), plant, and physician were included and followed up over a five year period for vital, health, and occupational status. The percentages of deaths observed among the exposed (1.8%) and non-exposed subjects (1.6%) did not differ. Eighteen (1.6%) and 15 (1.4%) cases of cancer were reported among exposed and non-exposed subjects, respectively (NS). One case of angiosarcoma of the liver occurred among the exposed group; six cases of lung cancer occurred among exposed subjects and two among non-exposed subjects (NS). The percentage of diseases of the circulatory system was higher (p less than 0.02) in the exposed group than in the non-exposed group: this difference was explained mainly by the high incidence of Raynaud's disease (p less than 0.006). The percentages of diseases of the respiratory system did not differ between the two groups.