A wrench-shaped ultrawideband (UWB) antenna with dual notched bands is proposed and investigated. The antenna has a wrench-shaped patch and two T-shaped slots on the ground, realizing the required UWB band. To achieve the dual notched band characteristics in upper and lower wireless local area network (WLAN) bands, an Omega-shaped slot is etched on the feedline and a novel composite right/left-handed electromagnetic bandgap (CRLH-EBG) structure is built on the ground. Measured results present an operating frequency band from 3.04 to 11.4 GHz, with two notched bands of 5.1–5.4 GHz (uplink of WLAN band) and 5.7−5.985.7-5.98 GHz (downlink of WLAN band), respectively. Both measured and simulated results of the proposed antenna are exhibited, promising that the antenna applies to UWB applications and can precisely overcome WLAN interference.