The Legislature last year voted to override Governor Beebe's veto of the Fetal Heartbeat Act.
The federal judge also blocked the provision to snatch away the license of doctors who performed abortions after twelve weeks.
But the judge still requires doctors to give ultrasounds to mothers so they can see the baby and hear a heartbeat.
Arkansas Right to Life supporters said that will be key to ending abortions.
They said research shows when a expecting mother hears a heartbeat she will change her mind about the procedure.
"We want to end legal abortions because it is wrong and it hurts women. It kills their unborn child and abortions don't help women at all. Many women who have abortions regret it afterward," said Rose Mimms, executive director of Arkansas Right to Life.
Mimms said allowing the ultrasound will show women that life begins at the moment of conception.
The ACLU calls this a victory, saying the judge agrees that the law was unconstitutional.