To study the association between the A to G transition at the -181-bp position in the promoter of matrix metalloproteinase-7 gene (MMP-7-181A/G) and susceptibility to adult astrocytoma, the MMP-7-181A/G polymorphism was genotyped by PCR-RFLP analysis among 221 adult astrocytoma patients and 366 healthy controls in a population of northern China. The result showed that the overall distribution of the MMP-7 genotypes among astrocytoma patients and healthy controls was significantly different (P<0.001). Compared with the A/A genotype, the G/G genotype significantly increased the risk to the development of astrocytoma (age and gender adjusted OR=2.77, 95% CI=1.27-6.02), while the MMP-7 A/G genotype only marginally increased the risk of developing this cancer (age and gender adjusted OR=1.66, 95% CI=0.99-2.84). Stratification analysis showed that the G/G genotype significantly increased the risk of astrocytoma only among male subjects (age adjusted OR=3.24, 95% CI=1.12-9.41) and individuals younger than 45 years (age and gender adjusted OR=3.16, 95% CI=1.09-9.16). When stratified by histological grades, a significant higher risk for developing grade II astrocytoma was observed among individuals harboring the A/G genotype (age and gender adjusted OR=2.06, 95% CI=1.05-4.05), while an about 3-fold elevation of risk to develop grades II, III, and IV astrocytomas was observed among individuals with the G/G genotype. The present result, for the first time, suggested that the MMP-7-181A/G polymorphism might be associated with the susceptibility to adult astrocytoma.