The lubricity of low sulfur diesel fuel was evaluated using a Scuffing BOCLE device. Physical and chemical properties of diesel fuels were then used to correlate with fuel lubricity. It is concluded that lubricity is primarily determined by viscosity and di-aromatic content. A lubricity predictor (Lp) using a linear combination of the two parameters is proposed to predict fuel lubricity. These two parameters are interchangeable within normal ranges of viscosity and di-aromatic content of No.1 and No.2 diesel fuels. Fuel lubricity has been interpreted to be the result of hydrodynamic lubrication, which is largely a function of viscosity, and boundary lubrication, which is contributed to by the di-aromatic content.