microRNAs (miRNAs) are an abundant class of small noncoding RNA molecules thought to be involved in biological functions, including embryonic development, chromosome architecture, cell proliferation and apoptosis. We hypothesized that common variants in the miRNAs are associated with risk of coal workers' pneumoconiosis (CWP). In a case-control study of 496 CWP patients and 513 control subjects frequency matched by exposure years and work types, we genotyped four single-nucleotide polymorphisms (SNPs) (rs2910164, rs2292832, rs11614913 and rs3746444) in pre-miRNAs (miR-146a, miR-149, miR-196a2 and miR-499) and assessed the associations with risk of CWP. A significantly increased risk of CWP was found for the miR-149 rs2292832 TT genotype (odds ratio (OR), 1.31; 95% confidence interval (CI), 1.01-1.69), compared with the CT/CC genotypes, and this increased risk was evident among subgroups of those aged > or =68 years (OR=1.52, 95% CI=1.03-2.25), dust exposure > or =26 years (OR=1.42, 95% CI=1.04-1.93) and ever smokers (OR=1.48, 95% CI=1.00-2.20). Furthermore, a significant association was observed between the genotypes and patients with stages II and III (OR=1.50, 95% CI=1.05-2.14 for stage II, and OR=3.33, 95% CI=1.67-6.65 for stage III). These results suggest that miR-149 rs2292832 polymorphism is involved in susceptibility to developing CWP.