A rapid and effective data analysis and interpretation approach is developed and validated for simultaneous determination of the film-mass-transfer and diffusion coefficients from time-limited experimental data obtained by dissolving gas in liquids by the pressure-decay method under isothermal conditions. Whereas previous approaches require experimental data until equilibrium and only determine the diffusion coefficient, accurate and rapid estimation of both parameters are achieved using a shorter set of time-limited data, thereby reducing the errors owing to swelling by significant gas dissolution at later times. The equilibrium conditions can be predicted theoretically stemming from an analysis of the time-limited data. This provides the estimates of the equilibrium pressure and gas solubility. This methodology not only yields accurate parameter values, but also alleviates the sufficiently large-time collection of pressure decay data needed to essentially achieve equilibrium. (C) 2008 American Institute of Chemical Engineers AIChE J, 55: 9-23, 2009