Methods, systems and devices for endometrial ablation. In accordance with a method, a working end of an RF ablation device is positioned in a patient uterus to contact endometrial tissue, the working end comprising a dielectric. Radiofrequency energy is applied for a first interval of time at constant power, the power being sufficient to capacitively couple current across the dielectric to the contacted endometrial tissue. A voltage parameter measured within the first interval, and radiofrequency energy is applied at a constant voltage over a second, treatment interval to ablate endometrial tissue, the constant voltage being related to the recorded voltage.