The present invention relates to a method of selecting transmission channels in a time data multiple access protocol and to a communication system using the method of the invention. Based on indications of transmission quality (Ci(t-k)) of each channel, stored during a time window (T), the method consists in selecting (S6) one channel that has the best current transmission quality indication position (Pi) relative to those stored during the time window (T). This method can be used to take advantage of independent variations in the quality of transmission of each channel while providing equitable access to the transmission resource.