Receiver circuits that can be reconfigured to generate test signals in a wireless device are disclosed. In an exemplary design, an apparatus includes a mixer and an amplifier. The mixer downconverts an input radio frequency (RF) signal based on a local oscillator (LO) signal in a first mode. The amplifier, which is formed by at least a portion of the mixer, amplifies the LO signal and provides an amplified LO signal in a second mode. In another exemplary design, an apparatus includes an amplifier and an attenuator. The amplifier receives and amplifies an input RF signal in a first mode. The attenuator, which is formed by at least a portion of the amplifier, receives and passes an LO signal in a second mode.