In the present work, a comparison of an integral and the two-dimensional boundary layer solution for the unsteady droplet vaporization problem has been made. The quasi-steady two-dimensional conservation equations (uncoupled from the liquid-phase) for the axisymmetric gas-phase boundary layer have been solved for both the circulating and the non-circulating droplets. The integral approach developed earlier (S. Prakash and W. A. Sirignano, Int. J. Heat Mass Transfer23, 253–268 (1980)) for the gas-phase analysis of the droplet vaporization problem has been modified and extended for time-dependent ambient conditions, namely temperature, pressure, fuel mass fraction and free stream velocity. The effect of variation of these ambient parameters on the droplet vaporization has also been studied. It is found that the integral approach is reasonably good in predicting the heat and mass fluxes as well as the velocity temperature and the fuel mass fraction profiles across the boundary layer. Also the droplet lifetime is predicted reasonably well by the integral approach. The difference of fuel mass fraction at the droplet surface and in the ambience, (YFs−YFe), through its effect on droplet surface temperatures affects the droplet lifetime, though not significantly. Also, the rate of droplet heating during the earlier part of the droplet lifetime has a significant effect on the vaporization rate and the droplet lifetime. The lower values of ambient pressure during the earlier part of the droplet lifetime result in higher vaporization rates. As expected, the mass vaporization rates are reduced and the droplet lifetime is increased because of drag.