In this paper, we develop a systematic design optimization methodology for switchable multi-band CMOS low noise amplifiers (LNA) in fully integrated multi-standard wireless receivers. We simultaneously optimize the performance of the LNA in each frequency band in order to ef- fciently design circuits with low noise that meet the speci fied impedance matching, gain, and power dissipation requirements. The results indicate that we are able to generate multi-band LNA designs with greater performance and fewer switchable components than those generated using traditional manual design techniques. Three design examples with up to 4 operating frequency bands demonstrate the versatility of the proposed method.