Correspondence: Chunhui Ni and Meilin Wang Department of Occupational Medicine and Environmental Health, School of Public Health, Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029, People’s Republic of China Tel +86 25 86862748 Fax +86 25 86527613 Email chni@njmu.edu.cn Objective: To investigate the possible relationship between macrophage migration inhibitory factor (MIF) -173 polymorphism (rs755622) and susceptibility to coal workers’ pneumoconiosis (CWP) in a Chinese population. Methods: A total of 699 patients with CWP and 677 controls were genotyped for the polymorphism by TaqMan method. Results: Our results showed that the MIF -173CC genotype was associated with a significantly decreased risk of CWP (adjusted odds ratio = 0.44, 95% confidence interval = 0.22–0.85), compared with the GG/GC genotype, particularly among smokers. Conclusion: Our results indicate that the functional MIF -173G/C polymorphism is involved in the etiology of CWP and susceptibility to this disease. Further studies are warranted to validate our findings.