The term “bacteremia” refers to the presence of bacteria in the bloodstream. Transient bacteremia is quite common, occurring during normal activities of daily life such as brushing one’s teeth or straining to stool. The majority of transient bacteremias are inconsequential because the innate host immune system clears the bacteria from the blood. Intermittent bacteremia occurs during focal bacterial infections such as pneumonia, osteoarticular infections, or pyelonephritis. Continuous bacteremia is present when the focus on the infection includes an intravascular site, such as a heart valve or an infected deep venous thrombus. The clinical presentation of a patient with bacteremia spans a broad spectrum ranging from fever without a source to life-threatening septic shock. Recognizing the signs and symptoms suggestive of bacteremia and understanding which laboratory tests and other supporting information help to identify the source of the infection are important skills for all providers. The systemic inflammatory response syndrome or SIRS criteria have been shown to be helpful in identifying patients who are likely to be bacteremic. Since early treatment with intravenous antibiotics reduces the morbidity and mortality that is associated with bacteremia and sepsis, they should be administered as soon as the diagnosis is suspected and blood cultures have been collected. Empiric treatment with broad-spectrum antibiotics should be reviewed at least on a daily basis and de-escalated to narrow-spectrum options once a specific bacterial pathogen has been identified, and its drug susceptibilities are known. Patients with sepsis have varying degrees of illness severity. The sepsis-related organ failure assessment or SOFA score is a screening tool that can be used to identify sepsis and to determine its severity. Patients who show signs of cardiovascular failure are said to be in “septic shock,” a condition that requires immediate life saving interventions. Cardiovascular support includes intravascular volume resuscitation, initially using isotonic crystalloid, such as normal saline or lactated Ringers solution. The use of vasopressor medications is often necessary to stabilize blood pressure and ensure adequate end-organ perfusion. Mortality is highest in those at the extremes of age and among those with preexisting comorbid conditions such as cancer, diabetes, immunodeficiency, and immune suppression.