AIM: To investigate the expression of matrix metalloproteinase-9(MMP-9) and nuclear factor of κB (NF-κB) in retinoblastoma (RB) and their relationships with differentiation and optic never infiltration for discussion their effect in invasion and metastasis of RB.METHODS:Immunohistochemical technique was adopted to examine the protein expression of MMP-9 and NF-κB in 47 cases. All the data were analyzed by statistics. RESULTS:The expression ratio of MMP-9 was 46.8%, and the expression was also significantly related to the differentiation degree(P<0.05) and never infiltration(P<005). The positive rate of NF-κB expression was 63.8%. The expression had notable relationship with the differentiation degree (P<0.05), but not correlated with the never infiltration (P>0.05). The expression of NF-κB had an obvious relationship with the expression of MMP-9 (P<0.05).CONCLUSION: In RB, MMP-9 expressed in higher level. NF-κB was activated and had higher expression in RB. The expression of NF-κB was related to the expression of MMP-9. The activation of NF-κB can possibly promote invasion and metastasis of RB by up-regulating the expression of MMP-9. Detecting the expression of MMP-9 and NF-κB may be biological indicator of invasion and metastasis of RB and can help to filter cases with high risk of metastasis. 