Jacyr Pasternak is an infectious disease physician and clinical microbiologist. He graduated from the Universidade de São Paulo Medical School in 1963 and after completed his residency in Internal Medicine at Hospital das Clínicas, he completed his education and became a hematologist. His interest to understand the reason why many patients died from infection led him to change gears and became specialized in Infectious Diseases in cancer patients. Dr. Pasternak was a distinguished fellow at Texas University Cancer Center, MD Anderson Hospital, infectious disease service directed by Dr. Gerald P Bodey from 1980 to 1981. His current activities include working as a clinical microbiologist at Hospital Israelita Albert Einstein Clinical Laboratory.