It had been thought that it is difficult to provide receipt-freeness in mixnet-based electronic voting schemes. Any kind of user chosen randomness can be used to construct a receipt, since a user can prove to a buyer how he had encrypted the ballot. In this paper we propose a simple and efficient method to incorporate receipt-freeness in mixnet-based electronic voting schemes by using the well known re-encryption technique and designated verifier re-encryption proof (DVRP). In our scheme a voter has to prepare his encrypted ballot through a randomization service provided by a tamper resistant randomizer (TRR), in such a way that he finally loses his knowledge on randomness. This method can be used in most mixnet-based electronic voting scheme to provide receipt-freeness.