Tri-n-butyl phosphate (TBP) is an excellent industrial solvent for metal extraction in the nuclear chemical industry. It is also being used as a major constituent of hydraulic fluids in the aircraft industry and other industrial applications. Risk assessment studies demand limiting of airborne concentration of TBP during normal as well as accidental exposure to humans, as the toxicity index for TBP is quite high. Published data on TBP vapor pressure has been analyzed, and an empirical equation is reported for the temperature range of 273.15 to 562.15 K. The performance of the reported equation is compared with the correlations available in the literature.