Different Klebsiella species may be responsible for various infections which may also differ with the site of the infection. These species may also present with different antimicrobial sensitivity patterns. However, the identification of Klebsiella to species level is not practiced in most of our hospitals, during bacteriological diagnosis, because of time constraints and labour. In view of these, antibiotics are normally administered to treat Klebsiella infections without considering the type of species responsible for that particular infection, or site of isolation of the Klebsiella species. This book therefore highlights the Klebsiella species responsible for causing infections, their sensitivity patterns to the commonly used antimicrobial agents and the effectiveness of empirical treatment based on sound laboratory research and a thorough study of literature.