Professor Jeffrey Zajac is Professor and Head of the University of Melbourne, Department of Medicine at Austin Health. He is a Clinical Endocrinologist and General Physician with research interests in molecular endocrinology.

He is Chairman of Medicine and Director of the Department of Endocrinology at Austin Health. Professor Zajac trained in Medicine at the University of Melbourne and undertook a PhD in the Department of Medicine, Austin & Repatriation Medical Centre. Following postdoctoral work in the Endocrine Genetics Unit at Massachusetts General Hospital, Boston, he returned to the University of Melbourne initially at Royal Melbourne Hospital and now Austin Health. His research group has embarked on a major research program investigating the effect of androgen deprivation therapy in patients with prostate cancer. These investigations include effects on bone, muscle, cardiovascular risk and metabolic state. He also heads a molecular endocrinology group investigating the androgen receptor using genetically modified mice. His clinical interests include: 1) general endocrinology; 2) the use, misuse and abuse of testosterone; 3) transgender medicine.