Covered employers are required to keep records in accordance with the recordkeeping requirements of the federal Fair Labor Standards Act (FLSA). No particular form of records is required, but employers having eligible employees are required to keep records containing the following information for at least three years:
If an employee is not subject to the FLSA’s recordkeeping requirements for minimum wage and overtime purposes (i.e., “exempt” employees), the employer need not keep a record of actual hours worked by the employee as long as eligibility for leave is presumed if the employee has been employed for at least 12 months, and with regard to employees who take leave intermittently or on a reduced leave schedule, as long as the employer and the employee maintain a written record of their agreement on the employee’s normal schedule or average hours worked each week.
Records and documents related to certifications, re-certifications, or medical histories must be maintained as confidential medical records in separate files from the usual personnel files. If the Americans with Disabilities Act (ADA) applies, these records also must be maintained in accordance with the ADA's confidentiality requirements (see 29 CFR 1630.14(c)(1)), except that--
If the Genetic Information Nondiscrimination Act of 2008 (GINA) is applicable, records and documents created for purposes of FMLA containing family medical history or genetic information as defined in GINA shall be maintained in accordance with the confidentiality requirements of Title II of GINA (see 29 CFR 1635.9), which permit such information to be disclosed consistent with the requirements of FMLA, stated above.
 29 C.F.R. § 825.500.