Starting Sunday, doctors will be required by law to notify the parents of girls younger than 18 who are seeking abortions.
Under the new law, doctors must notify the parents in writing, 48 hours before the procedure.
While there is no criminal penalty for doctors who break the law, they are liable for damages in civil court.
Colorado voters approved a notification law 5 years ago but it was struck down by the courts.
Tthe state legislature passed the new law this year.