Matrix metalloproteinases (MMPs) are a group of zinc-dependent peptidases that participate in matrix turnover in solid malignancies. The aim of this study was twofold. First, we sought to investigate under a case-control design the association between the functional -1562C/T polymorphism in the promoter region of MMP-9 and gastric cancer (GC) in a Turkish sample. Second, we examined its prognostic significance in GC patients. A total of 144 subjects were enrolled in the case-control study (79 GC cases and 65 controls). Overall survival (OS) and progression-free survival (PFS) served as the main outcome measures in the longitudinal study. The MMP-9 -1562C/T polymorphism was genotyped using a polymerase chain reaction-restriction fragment length polymorphism method. The odds ratio (OR) of GC for the CC genotype relative to the CT+TT genotypes was not significant (OR = 0.89, 95 % confidence interval [CI] = 0.44-1.82, P = 0.75). These results did not change after allowance for age and sex in multivariable regression analysis (OR = 0.81, 95 % CI = 0.40-1.94, P = 0.84). When the MMP-9 -1562C/T polymorphism was analyzed among GC patients in relation to OS and PFS, we found no significant differences between subjects with the CC and CT+TT genotypes. In conclusion, the results of our study did not point toward a major role of the MMP-9 -1562C/T polymorphism in the pathogenesis and clinical course of GC in Turkish subjects.