Ethanol is considered a promising alternative fuel due to its advantages when compared to conventional fossil fuels mostly because it is renewable, biodegradable, it has high octane number and latent heat of evaporation. Since droplets generally evaporate inside a vapor cloud in spray combustion, rather than burning individually, in a realistic setup, considering background fuel vapor concentration effects is crucial. Therefore, this work aims to investigate the effects of ambient fuel vapor concentration on the evaporation of a single ethanol droplet by means of numerical simulations to better understand its evaporation dynamics. The theoretical model is validated through numerical simulations of an ethanol droplet evaporation. The results show that condensation effects are observed for non- zero ambient vapor concentration at the beginning of the simulation. For low ambient temperature and high ambient pressure conditions, if the ambient fuel vapor concentration is high enough, the droplet does not evaporate. In this study, the ambient fuel vapor concentration is varied in the range of 0.0 to 0.75. The influence of ambient vapor concentration on the average area reduction rate is also investigated. Such influence is explained by the net result of mass and energy transfers factors. It is noticed that there is a threshold ambient temperature which determines whether the average area reduction rate will increase or decrease as function of the ambient vapor concentration.