We previously cloned and identified the esophageal cancer related gene 1 (ECRG1), a novel candidate tumor suppressor gene, from human esophageal cells. A single nucleotide polymorphism (Arg290Gln) was identified in the coding region of ECRG1 and might play a role in susceptibility to esophageal squamous cell carcinoma (ESCC). To examine this hypothesis, we analyzed 998 ESCC patients and 1252 controls in a hospital-based, case-control study in a Chinese population for this polymorphism. We observed a statistically significantly increased risk of ESCC associated with the ECRG1 290Arg/Gln and 290Gln/Gln genotypes compared with the 290Arg/Arg [odds ratio (OR)=1.23, 95% confidence interval (CI)=1.03-1.46; P<0.05]. A greater than multiplicative joint effect between the ECRG1 polymorphism and tobacco smoking exposure was also observed (OR=1.95, 95% CI=1.48-2.56; P<0.001). Furthermore, the elevated risk of ESCC associated with the ECRG1 polymorphism was increased consistently with cumulative smoking dose. ORs (95% CI) for 290Arg/Gln and 290Gln/Gln genotypes among non-smokers and smokers who smoked<or=27 and >27 pack-years were 1.03 (0.78-1.35), 1.91 (1.36-2.67) and 2.08 (1.48-2.92), respectively (P trend test<0.001). Taken together, our results indicate that the ECRG1 290Gln variant allele might be a genetic susceptibility factor for developing ESCC, especially in the smoking population.