With New York's Medicaid coverage already broader than federal law requires, the state expects to add about 75,000 people to the program next year under the federal health care overhaul.
The state also expects the program to pick up another 425,000 people who have been eligible but don't know it.
Medicaid, the government health insurance program for the poor, covers 5.1 million New Yorkers. That's more than one-fourth of the state's residents.
Separately, New York will begin enrollment Oct. 1 in a new health insurance exchange expected to enroll another 1.1 million New Yorkers who have no coverage but make too much money to qualify for Medicaid.
New York health officials are putting together a marketing plan to inform many of the state's 2.7 million uninsured.