This paper presents the results of a study on the effect of fuel physical properties, ambient temperature and fuel droplet initial diameter on droplet evaporation rates. The study was concentrated on comparison of evaporation rates for both diesel and Rapeseed Methyl Ester (RME). Based on results obtained from tests, a mathematical model is developed by using non-dimensional analysis.Tests were carried out at the atmosphere pressure with a temperature variation from 150°C to 250°C. A high-speed video system was used to observe and record images of suspended fuel droplets that were analysed with a purposely-designed image process method.A satisfactory agreement between test results and simulation data has been achieved. It is concluded that diesel fuel vaporisation is more sensitive to ambient temperature and initial diameter than RME droplets.