This work presents the dynamic simulation of rosemary essential oil extraction by steam-distillation. Experimental data acquired in an industrial steam-distillation unit were used to estimate the model parameters. Two distinct climatic conditions (summer and winter) were used to verify the model flexibility. In winter condition, two time-dependent experimental data curves were used together to verify the parameter estimation strategy, whereas in summer condition, two time-dependent curves were used for parameter estimation and a third one for model validation with respect to prediction. The mathematical model fitted satisfactorily both set of industrial data, resulting, for the summer and winter, in global mass transfer coefficient of 8.64 x 10(-4) s(-1) and 9.10 x 10(-4) s(-1), and equilibrium constant 2.72 x 10(-4) m(3)/kg and 1.07 x 10(-2) m(3)/kg respectively.