The time variations of the double layer capacitance and of the oscillation frequency of an electrochemical quartz microbalance are simultaneously recorded to determine the kinetics of adsorption of bovine serum albumin on a gold electrode. Both variations which can be fitted by a sum of exponential functions corroborate a consecutive irreversible step model already proposed. It is established that for the steps associated with a mass change both methods provide the same values for the time constants. This result validates the double-layer capacitance measurement method (which is indirect) as a tool for determining in situ the kinetics of protein adsorption. In addition to the information common to the two methods, these methods provide complementary information: number of adsorbed monolayers for the quartz microbalance; change of the layer structure at constant thickness for the double layer capacitance. Thus, according to the sign of the electrical charge of the interface, two or three monolayers are adsorbed end-on during the adsorption process. Finally, it is established that in our conditions the quartz oscillation modifies with respect to the non-oscillating quartz, the kinetics of adsorption and the structure of the adsorbed layer.