Method of identifying a protocol at the origin of a data flow. The method of identifying a protocol giving rise to a packet flow comprises the following steps: a capture of the flow of the protocol to be identified, statistical classification of the flow, comprising an extraction of the classification parameters and a comparison of the classification parameters with statistical models constructed during a learning phase. The statistical classification comprises: a first phase of global statistical classification; and a step of synthesis of the results of the first and second classification phases so as to identify the protocol giving rise to the flow.