Medical Investigation is an American medical drama television series that began September 9, 2004, on NBC. It ran for 20 one-hour episodes before its cancellation on March 25, 2005. The series was co-produced by Paramount Network Television and NBC Universal Television Studio.

The series featured the cases of an elite team of medical experts of the National Institutes of Health (NIH) who investigate unusual public health crises, such as sudden outbreaks of serious and mysterious diseases. In actuality, medical investigative duties in the United States are normally the responsibility of the Centers for Disease Control and Prevention (CDC) and local health departments, while the NIH is primarily a disease-research and -theory organization.