The variation of G>T in the MUC5B promoter (rs35705950) has been associated with idiopathic pulmonary fibrosis (IPF) and familial interstitial pneumonia (FIP) in Caucasians, but no information is available regarding this variant in the Chinese population. We recruited 405 patients with interstitial lung diseases (ILD), including 165 IPF patients and 2043 healthy controls, for genotyping the MUC5B gene in the Chinese population. One hundred three patients with pneumonia and 360 patients with autoimmune diseases (ADs) were recruited as disease controls. Our results indicated that the prevalence of the minor allele (T) of the polymorphism rs35705950 in healthy Chinese subjects was approximately 0.66%, which was lower than that described in the Caucasian population. The frequencies of the T allele were 3.33% and 2.22% in IPF and ILD patients, respectively, and these values were significantly higher than those of healthy controls (P = 0.001, OR = 4.332 for IPF, and P = 0.002, OR = 2.855 for ILD). A stratified analysis showed that this variant in MUC5B associated with the risk for ILD mainly in older male Chinese subjects. No difference was observed between patients with pneumonia, AD patients, and healthy controls.