An investigation was made to correlate post-mortem findings of pleural plaques (PP) with the smoking habits and occupational history of asbestos exposure of 898 adults from the general population. A significant association between PP and smoking was found in middle-aged and elderly men (p less than 0.001). When occupational history was considered, such an association was present in both exposed (p less than 0.01) and non-exposed (p less than 0.05) men aged over 50 years. No association was observed in non-exposed women, while in those exposed, the absolute number of cases was too small to evaluate any relationship. The number of cigarettes smoked did not correlate significantly with the frequency of PP. This autopsy study confirms the association between occurrence of PP and the smoking habits.