This paper presents a novel microstrip dual-band filter in which a shunt-stub bandpass filter and an open-stub bandstop filter are integrated into a single structure of short length. The bandstop filter is centered within the passband of the bandpass filter, resulting in a filter having dual passbands. Good return loss is obtained using an optimization routine. This method is suitable for designing dual-band filters having wide bandwidths. Good agreement between theory and measurements in respect of low insertion loss and high isolation is demonstrated.