Objective To explore the effect of the cardiac environment on skeletal myoblasts by measuring connexin43 (Cx43) gene expression in L6 cells and L6-Cx43 cells when co-cultured with cardiomyocytes. Double immunofluorescence staining was applied to detect the location of Cx43 in both L6 and L6-Cx43 cells. Methods Western blotting was used to detect Cx43 gene expression on protein level at different co-culturing time point. Results Data from Double immunofluorescence indicated that, Cx43 was expressed on interface between adjacent L6 cells and cardiomyocytes or between adjacent L6-Cx43 cells and cardiomyocytes when the two cell types were co-cultured EM>in vitro/EM>. Western blotting results showed that Cx43 protein level was increased in L6 cells and even more increased in L6-Cx43 cells. Conclusion Cardiac enviroment may induce skeletal myoblasts Cx43 gene expression, and direct cell-cell contact is necessary. This effect can be enhanced by Cx43 transfection.