AIM: To explore the relationship between matrix metalloProteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TTMP-2) in the development of colorectal carcinoma and to provide a valuable marker for clinical diagnosis.METHODS: Twenty-five patients with colorectal carcinoma underwent surgical resection. Samples were taken from tumor sites and normal tissues. MMP-2 activity was determined by gelatin zymography. Western blot and ABC immunohist ochemical staining were used to detect the expression levels of MMP-2 and TIMP-2 in normal and colorectal carcinoma tissues. Statistical analyses were performed using the Student's ttest and one-way ANOVA. P＜0.05 was considered statistically .significant. All the statistical analyses were performed using SPSS 10.0software. RESULTS: MMP-2 activity could be detected in both normal and colorectal carcinoma tissues. MMP-2 actMty in colorectal carcinoma tissues was much higher than that in normal tissues (P＜0.05, t =3.916, 4.227). MMP-2 adivity was positively related to the colorectal carcinoma invasion depth, lymph node metastasis and Duke's stage. Western blot and ABC immunohistochemical staining demonstrated that the expression level of MMP-2 in colorectal carcinoma tissues was much higher than that in normal tissues (P＜0.05, t = 9.429), but the expression level of TIMP-2 in colorectal carcinoma tissues was much lower than that in normal tissues (P＜0.05, t = 7.329). The MMP-2/TIMP-2 ratio of colorectal carcinoma was much higher than that of normal tissues. With the progression of invasion depth, lymph node metastasis and tumor Duke's stage, the activity and expression level of MMP-2 and TIMP-2 gradually increased, but the MMP-2/TIMP-2 ratio gradually decreased. CONCLUSION: The balance between MMP-2 and TIMP-2 plays a crucial role in the process of colorectal carcinoma invasion and metastasis.