It follows a five-year partnership and will help DSE to increase participation from regional to international level in both swimming and athletics.
It is also aimed at talent identification and team selection in the run-up to the Paralympics in Beijing in 2008 and London in 2012.
Philip Williamson, chief executive of Nationwide Building Society, said: "We like to think that our relationship with DSE has been a great example of how organisations can make a difference and we are delighted to be able to expand on our support.
"In partnership, we want to assist DSE with encouraging participation in sport. This means giving support where the champions start their road to success - at the grassroots level - and beyond."
