The pressure exerted by uterine contractions on the contents of the organ is described at different stages of pregnancy and labor. The tracings recorded are correlated with clinical information supplied by abdominal palpation and sensation of pain. The origin of the contractile wave, its propagation throughout the uterus and the coordination of the different parts of the organ are also described. Normal uterine physiology and its clinical applications are the main object of the chapter although brief consideration is made of deviations from the normal pattern. The mechanisms by which uterine contractions efface and dilate the cervix, distend the lower segment, and deliver the fetus and placenta are presented in detail. Special emphasis is given to the hemodynamic effects of the contractions. The response of the myometrium to levoepinephrin, levarterenol, estrogens, progesterone, relaxin and oxytocin are described and the possible significance of these hormones in the control of uterine activity during pregnancy and labor is briefly discussed.