In this paper, a novel Integrated Filter-Antenna (IFA) is proposed. The filtering element is based on the open-loop resonator bandpass filter with capacitive termination. The slot antenna is developed by a microstrip fed slot. This slot antenna not only provides overall good antenna performance, but also improves the stopband rejection of the filter. The simulations and measurements of a 900 MHz prototype bandpass filter and a 1.8 GHz slot antenna are presented in this work. The measured results have good match with the simulation. Compared to the filter structure without slot antenna, the stopband rejection is improved by 8 dB without increase the size of the circuit.