Future utilization of smart clothing will necessitate applications of multi-function and multifrequency wearable antennas. This work addresses the development of a dual-band textile antenna for wearable applications. The antenna is for GSM operation in the 1900 MHz band and for WLAN operation in the 2.4 GHz band. The proposed antenna has a U-shaped slot-structure mounted on the surface of fleece fabric. The proposed antenna structure is easy to attach to clothing and the structure does not limit the possible antenna placements. Details of the proposed antenna design are described, and the experimental results of a prototype are presented.