Layered double hydroxides (LDHs) intercalated with dodecanoic acid have been prepared by anion exchange with Mg/Al-NO3--LDHs as the precursor under acid condition with water and ethanol as the dispersion medium. The obtained materials were characterized by X-ray diffraction (XRD), thermo-gravimetric and differential thermal analyser (TG-DTA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and BET. Patterns of XRD and FTIR show that interlayer nitrate ions have substituted with dodecanoic acid and the gallery height has increased from 0.88 nm to 1.99 nm. The interlayer distance of the intercalated materials increases with the increase of pH value due to the different arrangement of interlayer anions. The tribological performance of LDHs precursor and intercalated LDHs in base oil were studied for the first time by using four-ball wear machine and gear testing machine. Experimental results show that the LDHs precursor and intercalated LDHs powder are excellent in friction-reducing, with decreases in friction coefficient by 23.9% and 22.2% respectively comparing with base oil. (C) 2012 Elsevier Ltd. All rights reserved.