Provided is a semiconductor memory device that is capable of internally controlling a strength of an output driver. The semiconductor memory device includes: an OCD (off chip driver) control signal generator for decoding EMRS and addresses to generate a plurality of external strength control signals or an internal driving signal; a self control signal generator for detecting a level of a driving voltage to generate a plurality of internal strength control signals in response to the internal driving signal; a control signal generator for generating a strength control signal in response to the external strength control signals or the internal strength control signals; and a data output driver for outputting data, the strength of the data output driver being controlled according to the strength control signal.