South Cambridgeshire councillors backed the new homes, a school and shops, which will be built by the A14 at Oakington.
Developer Gallagher and the Home and Communities Agency now aim to start construction work in the second half of next year, once details of how neighbourhoods will be phased and planning conditions are met.
The HCA will make land available to allow a secondary school to be built alongside first phase construction to take pupils from Northstowe and Longstanton.
Up to 10,000 homes are planned for Northstowe, making it the biggest new town in Britain since Milton Keynes.
Last week the Government said it would commit £7.7m to widen the A14 between Girton and Histon in 2014 as a short term measure to ease congestion in advance of the major upgrade to the road.