Background: Brachytherapy, also referred to as Curietherapy, is a form of internal radiation therapy utilizing radioactive sources positioned directly within or adjacent to tumor tissues. This technique is integral to oncology because of its accuracy in delivering high-dose radiation, lessening collateral damage to healthy tissues, and has evolved significantly since its inception in the early 1900s. Aim: The purpose of this paper is to outline the clinical indications and treatment guidelines for high dose rate (HDR) brachytherapy, focusing specifically on prostate and cervical cancers, highlighting its radiobiological principles, technical aspects, clinical outcomes, and safety measures Methods: This review consolidates existing literature and recent studies on HDR brachytherapy, examining the evolution of the method, key radiobiological mechanisms, physical principles, and various clinical applications. It also evaluates contemporary technological advancements, including imaging modalities (CT, MRI, Ultrasound), advanced dosimetry, and quality assurance procedures that enhance precision and safety in clinical practice. Conclusion:HDR brachytherapy represents a highly effective therapeutic modality characterized by precise radiation delivery, short treatment durations, and superior clinical outcomes, especially in prostate and cervical cancers. Continued integration of advanced imaging technologies, refined dosimetric planning, and robust multidisciplinary approaches are essential for optimizing patient outcomes and minimizing potential complications. The future of HDR brachytherapy is promising, supported by ongoing technological and methodological improvements.