The UK’s highest court dismissed appeals brought by Peter Chester and George McGeoch.
Chester, who is in his 50s, is serving life in Wakefield Jail for raping and strangling his seven-year-old niece Donna Marie Gillbanks in Blackpool in 1977.
McGeoch, from Glasgow, is serving his life sentence at Dumfries prison for the 1998 murder of Eric Innes in Inverness.
The latest round of their legal battle against the ban preventing them from voting while in prison was rejected by seven Supreme Court justices in London.
David Cameron welcomed the unanimous decision.
The Prime Minister tweeted: “The Supreme Court judgment on prisoner voting is a great victory for common sense.”
Chester is detained at Wakefield prison in West Yorkshire and the minimum term he was ordered to serve before becoming eligible to apply for parole has expired.
McGeoch received a minimum term of 13 years, but due to subsequent convictions, including taking two prison nurses hostage in a siege in 2001, will not be considered for parole until 2015.
The European Court of Human Rights ruled in 2005 that a blanket ban on serving prisoners going to the polls was incompatible with the European Convention on Human Rights (ECHR), relating to the right to free and fair elections.
The European court said it was up to individual countries to decide which inmates should be denied the right to vote from jail, but that a total ban was illegal.
Chester, who is also known as Peter Chester Speakman, originally had his voting claims rejected by the High Court in 2009.
His challenge at the Supreme Court followed a decision by three Court of Appeal judges in December 2010 when it was argued on his behalf that the serious nature of his offence did not justify disenfranchising him, and to do so was “disproportionate” and violated his human rights.
Mr Cameron has vowed that inmates will not be given voting rights under his administration and has said that the idea of giving prisoners the vote makes him ‘’sick’’.
He told the House of Commons last year: ‘’No-one should be in any doubt: prisoners are not getting the vote under this Government.’’
Under section three of the Representation of the People Act 1983, convicted prisoners are prevented from voting in parliamentary and local government elections - and under the European Parliamentary Elections Act 2002 a person is only entitled to vote in European parliamentary elections if he is entitled to vote in parliamentary elections.
In November the Government published the Voting Eligibility (Prisoners) Draft Bill for pre-legislative scrutiny by a joint committee of both Houses.
It has put forward three options - a ban for prisoners sentenced to four years or more, a ban for prisoners sentenced to more than six months and a re-statement of the existing ban.