—The distribution of the delay is a very important measure to determine the performance of a WLAN. Indeed, realtime applications typically require that their packets reach their destination within a certain delay with a given probability, and to guarantee this it is necessary to perform the computation of the delay distribution. In this paper we develop a novel method to compute the delay distribution of IEEE 802.11 Distributed Coordination Function (DCF) for a WLAN where the stations transmit packets of variable length. We develop an analytical model that applies to basic, RTS/CTS, and hybrid (coexistence of basic and RTS/CTS) access modes. A simulation model is used to validate the analysis.