A flexible monopole antenna for UWB systems is proposed. The proposed antenna has good performance over the entire UWB bandwidth, and it enhanced the impedance bandwidth by using the stepped CPW feed line. It can be easily mounted on conformal shape, because it is fabricated on PET film having the flexible characteristic. It has a band-notch function of 5 GHz WLAN band using two slits. From the results, it is observed that the proposed antenna has the similar radiation patterns and the return loss in comparison with the planar type monopole antenna, when it is rolled.