The adsorption kinetics of C14E8 at the air-water interface was investigated. A new approach to the determination of the adsorption isotherm and the evaluation of model parameters is proposed in this work. Besides the equilibrium surface tension gamma (C), a second set of equilibrium data [equation of state gamma(Gamma)] was measured and used to determine the adsorption isotherm and model parameters. Dynamic surface tension gamma (t) for the adsorption Of C14E8 onto a freshly created interface was measured and used to determine the controlling mechanism and diffusivity. The data of the equation of state play an important role in this study. No data for C14E8 are available for gamma (C) > 62 mN/m because an extremely long time is needed for solutions at very dilute concentrations to reach their equilibrium tensions. Equilibrium data, gamma (C) and gamma(Gamma), indicate that the adsorption Of C14E8 is anti-cooperative. The adsorption Of C14E8 onto a fresh interface is found to be diffusion-controlled. A diffusivity of 7.6 x 10(-6) cm(2)/s results from the best fit between the entire relaxation data of gamma (t) and the model predictions.