The rapid advances in the development of formulation and delivery systems based on micron-sized and nanoscale drug particles will create significant benefits to the pharmaceutical industry. Complementary to traditional methods, supercritical fluid techniques have found many useful, and sometimes unique, applications in the production and processing of drug particles. In this article background information is provided on a variety of supercritical fluid techniques relevant to drug formulation and delivery, recent advances and novel applications are highlighted, and the successful development of a new supercritical fluid rapid expansion technique for producing exclusively nanoscale drug particles will be discussed. Challenges and opportunities for further development and future applications are also reviewed.