The 49th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), traditionally one of the scientific highlights of the anti-infective professional year, was held in San Francisco in early September 2009. This comprehensive conference covered all important aspects of infectious diseases and anti-infective therapy. Of particular note, the release of information at ICAAC regarding the research and development of new antibacterial agents is highly anticipated by industry as well as the scientific and medical communities. As in the past, new compounds were revealed for the first time at the ICAAC and poster sessions were well attended, providing opportunities for animated discussions. This year's presentations and poster sessions reflected the challenging anti-infective drug development situation, yet they also provided deep insights and increased clarity regarding trends and future availability of new antibiotics. This report focuses on ICAAC presentations of new antibacterial drugs in research and development and future trends.