Jatropha oil has been known as alternative substitute for diesel fuel but its potential use as lubricant is not much known yet. This work is meant to investigate the effect of Tricresyl Phosphate (TCP) to jatropha oil which subjected to be used for transmission oil. Crude jatropha oil was used as base oil and 0.5-5 v/v. of TCP were added to crude jatropha oil. Commercial SAE 80W/90 grade transmission oil was used as comparison. Ostwald-Fenske capillary viscometer was used to characterize viscosity of jatropha oil and TCP mixture. Four- ball method was used to characterize friction and wear of the oil samples. No significant changes were found on viscosity by addition of TCP. Anti wear characteristics of crude jatropha was greatly improved by addition of TCP. No significant effect to friction coefficient also found at 40 kgf load, but addition of sufficient amount of TCP was able to reduce friction at 80 kgf load. © 2012 Asian Network for Scientific Information.