Customer's commitment has become a main meditating goal for many companies. It appears to be a promosing market segemntation criterion. In this sense, the present work focuses on commitment as a possible criterion to segment the consumers market. It starts by analysing the importance of consumer commitment for companies. After the review of the literature of commitment at different relationship levels, a definition and a multidimensional structure is proposed for this construct. The study performs a segmentation analysis of bank customers. Three clusters of client are identified according to their level of commitment. Main conclusion and its implications for marketing management are pointed out.