Mayardit is the first vice president of Sudan and has met Graham on two previous ocassions.
Samaritan's Purse said it has spent more than $60 million to help the Sudanese recover from civil war by supporting four hospitals, distributing food and establishing schools.
Mayardit met with President Bush Monday. Bush announced an airlift of equipment for humanitarian relief in the Darfur region of Sudan where millions of people have been driven from their homes.