Abstract: The Molybdenum N,N-dialkyldithiocarbamatcs (MoDTC), involving seven different alkyl groups, have been synthesized and characterised by elemental analyses, mass spectra, infrared and UV-vis spectral studies. The results obtained from Four-Ball test demonstrated that the anti-wear ablitity of Molybdenum N, N-didodecyldithiocarbamate and Molybdenum N, N-di (2-ethylhexyl)dithiocarbamate were better than others. Adding about 0.3%(wt) of these compounds into 500SN base oil, the Four-Ball wear scar diam. (d_(30)~(40)) was determined to be 0.42. The MoDTC were found to impose better mixing acting on the detergentdispersant additives employed in engine oil. Auger Electron Spectroscopy was used to study the reaction layers formed under Four-Ball conditions in the presence of MoDTC to determine the wear prevention mechanism of MoDTC.