This paper presents the saturation throughput analysis of IEEE 802.11g (ERP-OFDM) networks. The presented work is based on the Markov model previously introduced and validated by the authors in Szczypiorski and Lubacz (Lecture Notes in Computer Science, vol. 4516, pp. 1082–1093, Springer, 2007). In the present paper the saturation throughput is evaluated in different channel conditions as a function of frame length. Keywords WLAN · IEEE 802.11 · CSMA/CA · Modeling