AIM: To investigate the expression of matrix metalloproteinases 1 and 3 (MMP-1 and MMP-3) and their tissue inhibitors of metalloproteinases 1 and 3 (TIMP-1 and TIMP-3) in the conjunctiva of eyes with conjunctivochalasis (CCh). METHODS: The conjunctival tissue was obtained from the CCh patients and controls, the MMPs/TIMPs expression concentration was determined by enzyme-linked immuno-sorbent assay (ELISA) and immunofluorescence staining. The expression levels of MMPs/TIMPs in the CCh fibro-blasts were determined by analyzing its concentration in the cellular supernatant that was abstracted from the in vitro cultured CCh fibroblasts. RESULTS: MMP-1 and MMP-3 levels determined by ELISA were both significantly higher in the CCh group than that in the control group (P=0.042, 0.022, respectively), so was the levels of TIMP-1 (P=0.010). No significant difference in the expression of TIMP-3 in conjunctiva was found between the two groups (P=0.298). The expression of MMP-1 and MMP-3 were both up-regulated significantly in the CCh group (P=0.040, 0.001, respectively) on immuno-fluorescence staining. MMP-1 and MMP-3 expression in the fibroblasts were both significantly higher in the CCh group than that in the control group (P=0.027, 0.001, respectively), while neither the TIMP-1 nor TIMP-3 expression was significantly different between the two groups (P=0.421, 0.237, respectively). CONCLUSION: The overexpression of MMP-1 and MMP-3 in conjunctival tissue and fibroblasts may play an important role in the pathogenesis and development of CCh.