Some students at Cooper Union are staging a lock-in to protest the school's plan to start charging tuition for some of its programs.
Students said a group has barricaded themselves on the top floor of the school's Foundation Building.
Others demonstrated outside.
The college hasn't charged tuition for a century, but lately has run into financial problems.
Now the students are insisting on better money management and for the president to step down.
"I think we've really ignored the community in our fight to save the school and the administration has ignored the community," student Rachel Appel said. "I think that the city needs to know what a treasure is being lost, and I honestly believe if more people knew about the situation, we'd have more support."
The barricaded students say they won't leave the building until their demands are met.
Cooper Union and its students have been working to raise more money.
Earlier this year, the college president said he would give 5 percent of his salary to the General Fund.