Underinsured motorist coverage in Missouri is automobile insurance that covers you if the injuries you have sustained in an auto accident which was not your fault are greater than the insurance coverage afforded to the other driver that hit you.  In other words, underinsured motorist coverage can pay you additional money if you receive all of the money available to the other driver under his or her insurance policy.  Underinsured motorist coverage is not mandatory in Missouri, and you may or may not have this coverage. If you have this coverage, you probably paid an extra premium for it.  If you are not sure whether you have underinsured motorist coverage, call your insurance agent.