BiCMOS circuit performance at low supply voltages is discussed. The basic advantages of BiCMOS circuits are briefly reviewed, and then actual advantages of the BiCMOS gate and the BiCMOS sense circuits, which are typical BiCMOS circuits, are explained. Their advantages at low supply voltages are also discussed. BiCMOS gates, BiCMOS sense circuits, and combined circuits that include a BiCMOS sense circuit are two or three times faster than CMOS circuits down to a supply voltage of 2 V. BiCMOS circuits have high performance even at low supply voltages such as 2 V.