AIM: To investigate the expression of matrix metallopr- oteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in retinoblastoma (Rb), and their relationships with tumor development stage. METHODS: Immunohistochemical technique was used to detect the expression of MMP-2 and MMP-9 in 41 cases of paraffin embedded Rb samples. Quantitative analysis of the expression of MMP-2 and MMP-9 was assessed by HMIAS-2000 Color Pathologic Analysis System. The differences of the expression of MMP-2 and MMP-9 in each clinical and pathological stage were analyzed statistically. RESULTS: In all the 41 Rb specimens, MMP-2 and MMP-9 expression was found in tumor cells. The expression of MMP-2 and MMP-9 was significantly higher in tumors with optic nerve invasion than in tumors without optic nerve invasion (P <0.05); the expression of MMP-2 and MMP-9 was significantly higher in tumors of extra-ocular stage than in tumors of glaucomatous stage or intra-ocular stage(P<0.05). CONCLUSION: MMP-2 and MMP-9 exist in retinoblastoma cells. The level of MMP-2 and MMP-9 is related to optic nerve invasion and clinical stage of Rb, which suggests the expression of MMP-2 and MMP-9 could be connected to the invasion and development of tumor cells. Further research is needed for deeper understanding of the biological behavior and better evaluation of the prognosis of Rb.