A highly reconfigurable merged analog baseband (MABB) with not only tunable bandwidth (BW), gain, and order but also reconfigurable power, noise, and linearity is proposed for multistandard integrated wireless receivers in this brief. The MABB could arrange the total gain to different stages for noise and linearity tradeoffs by introducing the merged biquad topology. To save power, the operational amplifier (Opamp) for the proposed MABB can reduce the GBW, as long as it meets the GBW requirement for different BW, gain, and order. A flexible power-efficient high-GBW Opamp with an adaptive common-mode bias circuit is also proposed for the eighth-order active-RC MABB. The proposed MABB covers a cutoff frequency range from 200 kHz to 20 MHz, whereas the gain could be tuned between 0 and 72 dB. The proposed highly reconfigurable MABB is suitable for multistandard integrated wireless receivers.