Biopharmaceuticals have revolutionized the landscape of modern therapeutics, offering targeted treatments for a range of diseases. This review explores the classification, mechanisms of action, and therapeutic applications of biopharmaceuticals, highlighting their significance in oncology, autoimmune diseases, infectious diseases, cardiovascular diseases, and neurological disorders. The article also delves into the development and manufacturing processes, regulatory aspects, market impact, and challenges associated with biopharmaceuticals. Innovations and future directions, along with ethical and social considerations, are discussed to provide a comprehensive understanding of the role of biopharmaceuticals in advancing modern medicine.