The origin of brachytherapy is directly related to the discovery of radioactivity by Becquerel in 1896, which led to Marie and Pierre Curie discovering radium in 1898. The first successful radium brachytherapy was the skin irradiation of two patients with basal cell carcinoma in St. Petersburg in 1903. The surface mold and plaque treatments were followed by intracavitary techniques for cervical and endometrial cancer. A few years later, an interstitial radium brachytherapy technique was developed, and most body areas were treated with radium brachytherapy. In the 1950s, radium was replaced by artificial cobalt-60 and cesium-137. In the 1960s, iridium-192 was the most commonly used source of brachytherapy. During this time period, remote after-loading devices were developed, and improvements in imaging techniques and computer technology were adapted to brachytherapy. The evolution of brachytherapy has continued over the years, but many of the techniques have remained unchanged. The limited use of brachytherapy compared to conformal external radiotherapy may be due to its invasive approach, operative risk, technical difficulty, and long learning curve. Today with the development of imaging techniques and dose planning, individual treatment planning has become possible. The success of brachytherapy has increased with extensive technological advances, accurate three-dimensional dose distributions in the patient, and optimization of treatment planning. In this article, the history of brachytherapy will be briefly reviewed.