"It looked like something from the early '80s," the Republican presidential candidate said during an appearance on "Fox and Friends."
"It was basically a liberal versus liberal debate about who was going to give away the most free stuff," Rubio continued.
"Free college education, free college education for people illegally in this country, free healthcare, free everything."
"Their answer to every problem in America is a government program and a tax increase. That's all they prescribe, time and time again," Rubio said. 
Republicans have long criticized Democrats for their support of social programs, arguing it creates a dependence on government that the party exploits for electoral advantage.
Former Florida Gov. Jeb Bush, another GOP rival, defended himself after using the phrase "free stuff" when discussing black voters last month.
Rubio said the Democratic debate Tuesday night in Las Vegas played out as he predicted, with candidates such as Hillary Clinton attempting to run to the left of self-described democratic socialist Sen. Bernie Sanders (I-Vt.).