Clemens Peter Freiherr[1] von Pirquet (May 12, 1874 – February 28, 1929) was an Austrian scientist and pediatrician best known for his contributions to the fields of bacteriology and immunology. Born in Vienna, he studied theology at the University of Innsbruck and philosophy at the University of Leuven before he enrolled at the University of Graz where he became a doctor of medicine in 1900. He started practicing at the Children’s Clinic in Vienna. 

Keywords: Bacteriology; Immunology; Clemens Von Pirquet.