An ultra-wideband (UWB) flexible antenna with a dual band-notched property is designed in this letter. This antenna is fed by a coplanar waveguide (CPW) tapered transmission line to achieve an impedance bandwidth of 1.95-35 GHz for VSWR<3. A double C-shaped slot within the monopole radiation patch and two L-shaped slots etched on the ground are introduced to reject the bands of 3.5 GHz (3.1-3.9 GHz) and 5.5 GHz (4.7-5.74 GHz) respectively, which are assigned to WiMax and WLAN applications. A Rogers4350 substrate is used to realize a low profile (0.29λL×0.22λL×0.00065λL, where λL is the free-space wavelength of the lowest operating frequency). The measured results show that the antenna has a UWB omnidirectional radiation characteristic that is suitable for UWB wireless communications.