Infections are a leading cause of morbidity and mortality in the elderly. Altered host defences, a senescent immune system, chronic illnesses, and environmental factors all contribute to the aged's predisposition to infection. Infections can present in atypical fashion contributing to diagnostic and therapeutic delays. Awareness of altered antibiotic absorption, metabolism, and excretion in the elderly is essential to correct antibiotic selection and dosing. Additionally, antibiotic interactions with medications commonly used to treat chronic illnesses should be taken into consideration prior to antibiotic prescribing. Prevention of infectious complications in the elderly requires interest, education, vaccination, and early intervention.