Recombinant DNA technology encompasses the precise regulation of target gene expression for therapeutic purposes. This technology employs a strategic approach involving gene products that hold promise for the treatment and prevention of various diseases. The utilization of target proteins enables the safe, cost-effective, and scalable production of therapeutics. The interdisciplinary collaboration among fields such as genetic engineering, gene therapy, and biotechnology further enriches this technology. Overcoming initial reservations, recombinant drugs have now gained widespread acceptance and rapid commercial approval. The extensive applications of recombinant DNA technology extend to bioremediation as well as the treatment of severe diseases through gene therapy and genetic modification techniques. This book chapter aims to provide an in-depth exploration of the diverse range of applications and rapidly evolving techniques within the field of recombinant DNA technology, with a specific focus on medical applications categorized by product types and targeted diseases.