A Bronx nonprofit that runs nearly a dozen senior centers must pay back $800,000 in Medicaid funds, the Attorney General’s Office announced Wednesday.

Louis Vazquez, the executive director of home attendant service Regional Aid for Interim Needs, never got the required city approvals before using the funds to pay the mortgage on the agency’s headquarters at 811 Morris Park Ave., authorities said.

Vazquez remains under investigation for allegedly charging thousands of dollars in personal expenses — including dental and car-lease bills, on the organization’ corporate American Express cards, AG’s Office officials said.