In mammary cancers, and more especially at the stage of generalization, the detection of estrogen receptors plays a prominent role in the choice of treatment. Recent studies indicate that nearly half of cancers containing receptors are responsive to various hormone treatments while only a minority of cancers not containing receptors are responsive to the same treatments. The present review emphasizes the benefits of a quantitative dosage of these receptors compared to their simple detection. It also evaluates the predictive value of progesterone receptors as an additional test for hormonodependence. Finally, it analyses the part played by receptors dosage in the current therapeutic strategy as well as in the development of new clinical protocols.