The Contraception Research Branch (CRB) supports research in the synthesis and testing of a broad spectrum of male and female contraceptive agents. Successful development of new contraceptive methods for men and women has been a goal for many decades. From the inception of this program, the CRB has had a continuing need for a Chemical Synthesis Facility (CSF) capable of synthesizing potential anti-fertility agents on a laboratory gram scale to a relatively larger kilogram scale. The kilogram scale chemical agents are manufactured under current Good Manufacturing Practices (CGMP) for comprehensive contraceptive evaluation, including toxicology studies and preclinical safety studies before entering human clinical studies. The CSF provides the government with chemicals, chemical intermediates, steroids, drug candidates and drugs, which are either a new chemical entity (NCE) commercially unavailable or unduly expensive to obtain commercially. The areas of chemical synthesis for CSF consist of small molecule antagonist or agonists of protein targets including but not limited to active natural products, natural product analogues, active steroids estrogens, progestogens, androgens and their analogues. In addition, CSF has an important role in support of providing intermediates for the synthesis of many unnatural amino acids that may be incorporated into the preparation of unnatural peptide agonists or antagonists by another CRB’s contractor.