This chapter delves into the innovative and strategic re-evaluation of existing pharmaceuticals to discover novel anticancer applications. This approach leverages the extensive clinical and pharmacological data available for approved drugs, significantly accelerating drug development and reducing associated costs and risks. The chapter outlines the drug repurposing methodologies, including computational approaches, high-throughput screening, and biological assays. It highlights case studies of successful repurposing endeavors that have led to groundbreaking advancements in cancer therapy. By exploring the potential of repurposing existing therapeutics, this chapter underscores the promising horizon of discovering practical and safer cancer treatments, ultimately contributing to the evolving landscape of oncology. Repurposing therapeutics for anticancer activity has developed as a promising approach to fast-track the development of novel cancer treatments. This entails identifying existing drugs, initially designed for other therapeutic indications that exhibit potent anticancer effects. Drug repurposing offers advantages such as reduced development timelines and costs compared to de novo drug discovery as it leverages existing clinical data and safety profiles. This chapter explores various examples of repurposed therapeutics with anticancer potential, highlighting mechanisms of action, preclinical and clinical evidence, and challenges and opportunities in this rapidly evolving field. Critical considerations for successful repurposing strategies, including drug screening methodologies and regulatory pathways, are also discussed to provide insights into the future directions of anticancer drug development.