A fully integrated multi-band power amplifier (PA) using a 0.25 m silicon germanium (SiGe):C process with an output power of above 25 dBm is presented. The behaviour of the amplifier has been optimised for multi-band operation covering, 2.4, 3.6 and 5.4 GHz (ultra wide band-worldwide interoperability for microwave access) frequency bands for higher 1-dB compression point and efficiency. Multi-band operation is achieved using a multi-stage topology where parasitic components of active devices are also used as components for matching networks, in turn decreasing the value and number of matching components. Measurement results of the PA provided the following performance parameters: 20.5 dBm 1-dB compression point, 23 dB gain and 7 efficiency at the 2.4 GHz band; 25.5 dBm 1-dB compression point, 31.5 dB gain and 17.5 efficiency at the 3.6 GHz band; 22.4 dBm 1-dB compression point, 24.4 dB gain and 9.5 efficiency at the 5.4 GHz band. Measurement results show that usage of both multi-stage topology and parasitic components as part of the matching network have provided a wider band operation with higher output power levels, above 25 dBm, with SiGe:C process.