During the hearing, held jointly by two House Oversight subcommittees, GOP lawmakers highlighted several instances of alleged fraud.
Kucinich though said the health reform overhaul provided remedies for preventing future fraud and waste.
He blasted the House GOP for targeting the healthcare law in its budget and for supporting provisions that would leave the "bulk of" Medicaid anti-fraud efforts to the states.
The healthcare law mandated stronger penalties for fraudulent Medicaid providers and included new enrollment requirements to help the Center for Medicare and Medicaid Services (CMS) to identify them more quickly, among other provisions aimed at fighting fraud.
Kucinich also defended CMS and its director, Cindy Mann, for "taking the threat of healthcare fraud very seriously."
"CMS has moved quickly and aggressively to stand-up its office of Medicaid Program Integrity," he said.
Republicans, meanwhile, raised questions about the law's expansion of Medicaid given instances of fraud in several states.
Rep. Michele BachmannMichele Marie BachmannBoehner says he voted for Trump, didn't push back on election claims because he's retired Boehner: Trump 'stepped all over their loyalty' by lying to followers Boehner finally calls it as he sees it MORE (R-Minn.) expressed "shock" at what she called the lack of accountability and transparency in the program.
She announced that she is working on a bill to require independent, third-party audits of Medicaid. "The Medicaid Integrity Act" will be introduced in the coming weeks, her office said.
"A game has been played where managed-care organizations can charge virtually anything they want for any expense they want because there is no one making sure that they are charging [fairly]," Bachmann said.
She added that "ObamaCare" will expand Medicaid spending in Minnesota by 21 percent.
"We don't have an accurate pulse of where this money is going today … What will we do [in Minnesota] when it is 21 percent more?" she said.
Rep. Jim Jordan (R-Ohio), who chaired the hearing, called fraud in Medicaid an "unmitigated disaster."
He argued that the healthcare law "will undoubtedly make waste, fraud and abuse much worse."