As noted by the California Association of REALTORS last week, Wells Fargo announced a surprise policy reversal in January regarding FHA loans. While competitive institutional lenders are raising FICO limits to 620 or better, Wells Fargo is lowering those limits to as low as 500. For FICOs between 500 and 579, the down payment requirement is 10%, and the down payment cannot be a gift from a relative. Borrowers with FICO scores of 580 to 619 will need to put down a minimum of 5%.
For home buyers with FICOs above 620, the minimum down payment requirement remains at 3.5% and gift funds can be used. Seller concessions toward closing costs remain at a maximum of 3% of the purchase price.
But it's not just FHA
This list says the min score for FHA is 530, but I don't know how old it is. http://www.fha-world.com/credit-score.html
Fannie Mae requires a minimum score of 620
Freddie Mac requires a minimum score of 620
FHA requires a minimum score of 530
VA requires a minimum score of 530
USDA requires a minimum score of 620
Portfolio requires a minimum score of 640