The interaction of connexin 43 and E-cadherin may play an important role in carcinogenesis and malignant behaviour of tumours. In this study, we examined the relationship between connexin 43 and E-cadherin in human non-small cell lung cancers (NSCLC). Expression levels of connexin 43 and E-cadherin were examined in 107 NSCLC specimens by immunohistochemistry. The connexin 43 gene was transfected into lung cancer LH7 cells. The protein localizations and levels of connexin 43 and E-cadherin were detected using immunofluorescence staining and western blot. Cell cycle and proliferation of lung cancer cells were examined using flow cytometry and MTT. We found that reduced expression of both connexin 43 and E-cadherin significantly correlated to poor differentiation, advanced TNM stage, and lymph note metastasis of NSCLCs. Connexin 43 and E-cadherin expression significantly correlated with each other. Over-expression of connexin 43 significantly induced E-cadherin expression. Moreover, connexin 43-transfected LH7 cells showed significantly decreased cell proliferation. The percentage of cells in G1 phase increased, while the number of cells in S and G2 phases significantly decreased. We concluded that concurrent reduction of connexin 43 and E-cadherin may contribute to the development of lung cancer. Connexin 43 may induce E-cadherin expression and inhibit cell proliferation and progression of lung cancer.