The budget proposals have already drawn criticism from Democrats due to its large cuts to the social safety net, which includes programs like Medicaid. And while the president has proposed reducing funding for programs like Medicaid and the Centers for Disease Control and Prevention, it would increase funding for the military and border security.
Critics have argued that the proposal "double-counts" a projected $2.1 trillion in revenue growth, which is currently used to both pay for tax cuts and bring down the deficit.
Some Republicans have also acknowledged that the $4.1 trillion budget is unlikely to pass as proposed, with some vehemently opposing certain provisions.
Mnuchin is expected to speak at the House Ways and Means Committee at 2 p.m. E.T. Watch his testimony live above.