Dr. Jose Katz, 68, pleaded guilty to falsifying charts diagnosing patients with angina and other heart ailments so he could prescribe extra tests and treatments when hundreds of patients did not need them.
In court Wednesday, he agreed his actions could have caused "serious bodily harm" to his patients.
He and his lawyer disagreed when prosecutors said some patients were at risk of death due to his actions.
In all, Katz admitted his scheme took in over $19 million. Katz's crimes went on from at least 2004 through 2012.
Katz faces up to 10 years in prison on the conspiracy to commit health care fraud charges. He also admitted creating a no-show job in his office in order to rip off more than $250,000 in Social Security benefits.