Osteosarcoma (OSA) is the most common adolescence cancer among all primary bone tumors next only to multiplemyeloma. It has a substantially worse prognosis and ability to metastasize to lung. MMPs (matrix metalloproteinases) are among the major proteases that take part in regulation of ECM (extracellular matrix). MMPs play an active role in the formation of the osteoid tissue, rich in collagens and other ECM proteoglycans. They also take part in pro-osteoclast, osteoclast, osteoblast, and osteoid formation. Many members of the MMP gene family have been linked to human cancers. It has been shown that MMPs particularly play a role in the tumor's acquisition of an invasive and metastatic character. In our study, the E45K and T102T polymorphisms of MMP-3 were studied using the PCR-RFLP method in 135 Turkish subjects (54 subjects with osteosarcoma and 81 healthy controls). We found that frequencies of E45K G allele (p:0,010, χ²:6,710, OR:1,429, 95% Cl: 1,019-1,858) and AG genotype (p:0,001, χ²:14,753, OR:2,32, 95% Cl: 1,491-3,626) were elevated in patients compared to controls. Besides, there was a significant difference in.E45K AA genotype between study groups (p:0,004, χ²:8,182, OR: 2,929, 95% Cl: 1,38-6,19). There were no significant differences between any genotypes or allele in the control and patient groups for MMP-3 T102T polymorphism. Our findings indicate that the G allele and AG genotype of MMP-3 E45K polymorphism is associated with increased risk of osteosarcoma in adolescent population of Turkey.