An endometrial ablation apparatus and method wherein an RF current having a frequency of between 250 kHz and 100 MHz is passed through the entire surface of an endometrium in order to provide heating of the endometrium. An electroconductive expandable member such as a balloon is used as the medium for passing the current and causing the heating of the endometrium. The temperature of the endometrium is raised to a temperature between 45.degree. C. and 90.degree. C. and preferably not above 70 for a time sufficient to destroy the cells of the lining while maintaining the average temperature of the myometrium at a temperature below approximately 42.degree. C. The expandable balloon is connected to a power source which provides the radio frequency power having the desired characteristics to selectively heat the endometrial lining to the desired temperature. The balloon can be constructed with an electroconductive elastomer such as a mixture of polymeric elastomer and electroconductive particles or can be a non-extensible bladder having a shape and a size, in its fully expanded form, which will extend the organ and effect contact with the endometrial lining to be destroyed. The electroconductive member may consist of a plurality of electrode area segments having a thermistor associated with each electrode segment whereby the temperature from each of said plurality of segments is monitored and controlled by a feedback arrangement from the thermistors.