What CME activity records am I required to keep? (And for how long?)

ACCME-accredited providers are required to have mechanisms in place to record and verify physician participation for six years after the date of the CME activity.  Sign-in sheets are an option, but not required.  As for activity documentation other than physician participation, providers are required to retain activity files/records of the CME activity planning and presentation during the last accreditation term or for the last twelve months, whichever is longer.