The type of the applications for which Internet is being used has changed over the years. Multimedia applications, Real-time applications and Game playing require Quality of service. IEEE has proposed IEEE 802.11e, a quality of service extension to the wireless LAN standard IEEE 802.11. In this paper service differentiation ability of 802.11e is evaluated. Identical traffic is considered for all Access categories to quantitatively differentiate different Access categories. The results indicate, 802.11e achieves service differentiation with some limitations. NS-2.26 is used for simulation.