The Coroner is an independent official with responsibility under the law for the medico-legal investigation of certain deaths occurring in San Mateo County.

The Coroner's office must inquire into the circumstances of sudden, unexplained, violent and unnatural deaths. This may require a post-mortem examination sometimes followed by an inquest. The Coroner's inquiry is concerned with establishing whether or not death was due to natural or unnatural causes. If a death is due to unnatural causes, for example in a road traffic accident, accident at work or by drowning, then an inquest must be held by law.