A special arrangement of electrodes and a differential system were employed for measuring the lateral conductance of Langmuir monolayers. Such an experimental system obviates the major difficulties inherent in this type of measurement which may have prevented the enhanced conductance from being observed in recently published data. It is shown unequivocally that both dc and ac conductances of monolayers increase when the monolayer is compressed beyond a critical density, thus resolving a controversy from the literature. ©1995 American Institute of Physics.