Electron transfer through a Langmuir-Blodgett monolayer of hexadecylquinolinium tricyanoquinodimethanide (C(16)H(33)Q-3CNQ) sandwiched between metal electrodes is studied carefully. Either current rectification (rectification ratio as high as similar to 20) for positive bias applied on the metal overlayer or symmetric current voltage curves were observed for samples with the highest resistivity. More leaky devices (resistivity of about a decade lower) show rectification (with a smaller ratio less than or equal to 5) for a negative bias on the top electrode. These results are analyzed regarding various mechanisms: (1) Aviram and Ratner proposal for a molecular diode, (2) geometrical asymmetry of the metal/Langmuir-Blodgett monolayer/metal structure, and (3) a polarization charge density effect. This study leads us to confirm that the observed electron-transfer properties through the C(16)H(33)Q-3CNQ LB monolayers are not only due to possible geometrical asymmetry in the metal/LB monolayer/metal structure but are also related to the strong asymmetry of the donor-pi-bridge-acceptor C(16)H(33)Q-3CNQ molecules.