A compact UWB G-shaped printed monopole antenna with reconfigurable band-notched characteristic is presented. The antenna design having a low profile of 8 × 27.5 mm2 consists of a G-shaped radiating element size of 8 × 8 mm2 fed by a microstrip transmission line with a matching line and a defected ground structure. In order to achieve reconfigurable characteristic, a pin diode is inserted between the poles of G-shaped radiator. When the pin diode is at ON-state, G-shaped patch behaves like a ring radiator and the antenna thus operates at whole UWB frequency. On the other hand; when the pin diode is at OFF-state, the antenna has a band-notched characteristic corresponds to C-band and WIMAX band spectrum. The antenna design is parametrically investigated and the proposed design is verified by a prototype. From the measured results, the antenna has switchable characteristic between whole UWB spectrum of 2.8-12.6 GHz at ON-state and stopped band of 3.5-4.95 GHz at OFF-state. Therefore, the proposed antenna excels in terms of geometry's simplicity, compactness, near omnidirectional pattern, high efficiency as well as band-notched configurability.