Amends the Cook County Article of the Illinois Pension Code. Provides that a contributing employee may elect to purchase creditable service for up to 48 months of active-duty military service, whether or not that service followed service as a county employee. Provides that to establish this creditable service, the contributing employee must pay to the Fund an amount determined by the Fund to represent the employee contributions for the creditable service based on his or her rate of compensation after the military service, plus interest at the effective rate from the date of discharge to the date of payment. Removes an existing provision concerning the purchase of service credit for military service. Amends the State Mandates Act to require implementation without reimbursement.