At a rally in Raleigh, the state capital, Cooper signed paperwork to veto the bill as a crowd chanted "veto."
"This bill has nothing to do with making women safer and everything to do with banning abortion," Cooper said, calling on Republicans to reconsider their stance.
Tami Fitzgerald, executive director of the anti-abortion group North Carolina Values Coalition, criticized Cooper for vetoing the bill and for holding his rally the day before Mother's Day.
That would make it more difficult for out-of-state abortion seekers to obtain the service in North Carolina.
Near-total abortion bans have taken effect in 14 states since the U.S. Supreme Court revoked federal abortion rights in June 2022, according to the Guttmacher Institute, an abortion rights advocacy research group.