Trichloroethylene (TCE) is a halogenated aliphatic organic compound frequently detected as pollutant in soils and ground water. In order to study the fate of TCE in water and to devise effective remediation strategies, a series of advection-diffusion (dispersion) models, where the diffusion coefficient of TCE (DTCE) is an important parameter, have been developed. However, DTCE in water has never been experimentally determined and only theoretical values (≃ 1 × 10−5 cm2,s−1 at 25°C) are present in the literature. In this paper we present a new method based on the Taylor dispersion technique, which allows to measure DTCE in a broad range of temperature and, in principle, in any solvent. We found that at 25°C DTCE = 8.16±0.06 × 10−6 cm2 s−1 and the value increases almost linearly with the temperature, while, in the limit of the experimental error, is independent from [TCE] for dilute solutions. From the temperature dependence of DTCE it was possible to calculate the specific TCE fitting constant in the well known Wilke & Chang theoretical relation and the activation energy of the diffusion process through the Arrhenius plot. This article is protected by copyright. All rights reserved.