Origins of antibiotic drug discovery are frequently traced to 1929 when Alexander Fleming recognized the antibacterial activity of a substance secreted by Penicillium notatum on a contaminated culture plate. However, the subsequent development of penicillin as a therapeutic agent was not realized until the early 1940s, after a consortium of academic and pharmaceutical scientists from England and the United States developed sufficiently advanced fermentation technology to produce high-purity penicillin in large enough quantities for medical supplies. It was at this time that the antibiotic era was truly successfully launched. During the following decade, unprecedented antibiotic research and development emerged in academic laboratories and the pharmaceutical industry, resulting in identification of most of the antibiotic classes currently used therapeutically. This short historical commentary describes some of these early events, beginning with a conference held at the New York Academy of Sciences in 1946, the first conference to focus entirely on the latest science related to the identification and characterization of antibacterial substances produced by microorganisms.