McCanns set for May showdown.
The meeting with the Home Secretary is being arranged following an exchange of letters between the couple and May.
Details of the meeting are still being confirmed. The couple, from Rothley, Leicestershire, want a review of all the information in the hands of the British and Portuguese authorities.
But the Metropolitan Police said they had no plans to reopen the investigation.
Madeleine was nearly four when she went missing from a holiday flat in Praia da Luz in the Algarve, Portugal, on the night of May 3, 2007.