Yes, if you were a member of another Massachusetts Public Retirement System subject to the provisions of M.G.L. Chapter 32 and you withdrew your retirement contributions, you may be eligible to buy back that prior service.   You must repay the original amount of the refund, plus interest to the date of the repayment.  You may complete the buy back as a lump sum payment, pre-tax rollover or in some circumstances through a deferred compensation plan within 5 years from the date of the agreement.