DNA-repair ability was estimated in a group of vulcanizers by measuring in vitro UV-induced unscheduled. DNA synthesis (UDS) in peripheral lymphocytes, and compared with that of an adequate control group. A considerable interindividual variability was shown by the UDS responses of the subjects studied both in the control and exposed population. Significantly (P = 0.0158) decreased UDS values were observed among the vulcanizers as compared to the referents. Neither age nor cigarette-smoking was observed to affect the UDS response, thus suggesting an association between the industrial exposure and decrease in the DNA-repair rate.