Job Creation and Affordable Housing Act of 2010 - Directs the Secretary of the Treasury to make a grant to each state equal to such state's low-income bond-subsidized housing election amount. Defines "low-income bond-subsidized housing election amount" as an amount a state may elect which does not exceed 85% of the state's bond-subsidized credit amount for low-income buildings.
Requires states to use grants to make subawards to finance the construction or acquisition and rehabilitation of qualified low-income buildings. Requires the return of grant funds not used to make such subawards before January 1, 2012.
Amends the Internal Revenue Code to: (1) deny a low-income housing tax credit for bond-subsidized buildings that received a subaward under this Act; (2) allow a five-year carryback of unused low-income housing tax credit amounts and a carryback for new low-income housing investments in 2010 and 2011; and (3) allow a full offset of low-income housing tax credits against regular income tax liability.