A comprehensive list of drug transporters has recently become available as a result of extensive genome analysis. Membrane transporters play important roles in determining the pharmacokinetic aspects of intestinal absorption, tissue distribution, and the urinary and biliary excretions of a wide variety of therapeutic drugs. The identification and characterization of transporters responsible for the transfer of nutrients and xenobiotics, including drugs, is expected to provide a scientific basis for understanding drug disposition, as well as the molecular mechanisms of drug-drug/drug-food/drug-protein interactions and inter-individual/inter-species differences. This review focuses on the influence of transporters on the pharmacokinetics of beta-lactam antibiotics, new quinolones, and other antimicrobial agents, as well as focusing on the drug-drug interactions associated with transporter-mediated uptake from the small intestine and transporter-mediated elimination from the kidney and liver.