Under Minnesota law, employees cannot be required to take lie-detector tests, but they may volunteer to do so.  Minnesota law prohibits employers from directly or indirectly soliciting or requiring “a polygraph, voice stress analysis, or any test purporting to test the honesty of any employee or prospective employee.”  See Minn. Stat. § 181.75.  It is also unlawful for anyone to sell or interpret lie-detector tests of employees or prospective employees if the individual knows that the lie-detector tests have been solicited or required by an employer.
Lie-detector tests may be administered by employers only in the rare situation in which an employee requests a polygraph test.  When this occurs, Minnesota law requires that the employer must inform the employee that taking the test is voluntary.  However, the employer may not tell anyone that the test was administered to the employee because Minnesota law prohibits anyone from disclosing the fact that another person has taken a polygraph or honesty-test, except to the individual tested or persons authorized by the individual to receive the results.  See Minn. Stat. § 181.76.