An evaluation of the relationship between silicosis and smoking is important in exploring the etiology of silicosis, and the relationship could have an impact on studies dealing with silicosis and lung cancer. Data addressing this relationship were found in studies designed explicitly to evaluate this association and studies that explored other questions. Studies based on compensation registers were excluded. Smoking data and methods varied across the studies considered. Of the 13 studies, 3 supported the hypothesis that smoking was positively associated with silicosis, 8 provided limited support (most included subpopulations showing positive associations), and 1 did not support the hypothesis. The only autopsy study suggested an inverse association. It is unclear whether the generally positive results indicate that smoking predisposes to silicosis or that nonspecific radiographic appearances from smoking were interpreted as silicosis in some studies. A positive association between radiographic silicosis and smoking would bias studies of silicosis and lung cancer, especially those lacking smoking data.