A dual-band fully integrated transceiver for IEEE 802.11a/b/g/j/n wireless local area network (WLAN) was implemented using 0.13 μm complementary metal-oxide semiconductor technology. The proposed hybrid up/down-conversion architecture, which is mixed double- and direct-conversion, was employed in 5 and 2.4 GHz bands, respectively, in order to eliminate the needs for high local-oscillator frequency generations. The hybrid up/down conversion transceiver was archived with small silicon size by block sharing, including such things as mixer sharing for each band, low-pass filter sharing between RX and TX chain and load inductor sharing of the low-noise amplifier and mixer of the Rx chain. The error vector magnitude (EVM) limit of the proposed receiver was measured to be 3.4/3.1 in the 2.4/5 GHz band, respectively. The Tx EVM was measured under the average output power of 12 dBm with external power amplifier to be 2.9/3.5 in the 2.4/5 GHz band, respectively.