The study estimated that 456,000 uninsured Ohioans just above and below the poverty line would gain health care under the expansion.
The group releasing the report said it would not say whether it thought Ohio should expand Medicaid.
"Our intention was to look at this from as many angles as we could," said Amy Rohling McGee, president of the Health Policy Institute of Ohio, who cautioned that numbers in the report are projections and could change slightly.
"This analysis is not inconsistent with what we have heard from the wave of hospitals and other stakeholders that have been urging the state to expand Medicaid," said Eric Poklar, of the governor's Office of Health Transformation. "We will continue to review all of the data at our disposal and feedback from stakeholders, both for and against, and recommend in the budget a course of action that is best for Ohio."
Kasich plans to make known his decision on whether to expand Medicaid when he releases his next budget on Feb. 4.