In western blotting, the electrophoretic transfer effect of the proteins can be affected by sodium dodecyl sulfonate (SDS) in the transfer buffer. Using three transfer buffer with or without SDS in both semidry and tank transfer systems, the Bcl-2 protein levels were tested and the spectrum of the protein blots were compared. The addition of SDS in buffer reduced the binding of Bcl-2 protein with PVDF membrane, either in semidry or tank electric transfer. The transfer efficiency of both semidry and tank systems were also compared. The semidry electric transfer markedly minimized the transfer times, but the transfer result were a little poorer than the tank transfer system.