Students at University College Dublin have voted to split from the Union of Students in Ireland.
USI has said it regrets the decision and is disappointed to lose the voice of UCD students from the national union.
It said it hoped to win back their support over the coming year.
"No" campaigners at UCD said the vote was the result of frustration with USI, including its failure to address costs and pass savings on to local unions.
No to USI spokesperson John McGahon said: "As students go through difficult times, never has there been a greater need for a radical re-focus in the student movement."