"Last night, I checked myself in to the Betty Ford Center in California to treat my addiction to alcohol," the 44-year-old Sullivan said.
He said he would be taking a temporary leave of absence from Congress, but made no mention of his future political plans.
Sullivan first was elected to Congress in 2002 to replace Steve Largent, who made an unsuccessful run for governor.
"I value my relationship with the citizens of Oklahoma's First Congressional District, whom I am privileged and honored to have served for the past eight years. So, I wanted to be open and honest on this tough situation," the conservative Republican said in his statement.
"I ask for your continued support and prayers as I face the challenges that lay ahead. I look forward to returning to serve and work for you in the House of Representatives as soon as possible."
"My family is going through a difficult time right now and I ask that you respect their privacy and keep us in your thoughts and prayers. With God's help and strength, I will get through this most challenging time in my life."
John Tidwell, a spokesman for Sullivan, declined to elaborate on the statement by his boss.
"The statement speaks for itself and I am not entertaining any questions at this time," Tidwell said.
Sullivan has acknowledged being arrested when he was 20 for public intoxication.
An aide to Sullivan said in 2002 that the new congressman was arrested when he was 17 on a misdemeanor assault charge for fighting with another teenager and at 18 for trespassing and loitering.
Court records later showed the scuffle was with an off-duty Tulsa police officer.
In 1992, Sullivan was taken into custody over an unpaid speeding ticket, but said he did not consider that an arrest because he was not placed in a jail cell.
Sullivan upset Cathy Keating, the wife of two-term GOP Gov. Frank Keating, in the primary for the 2002 special election in the heavily Republican 1st District, which includes Tulsa. He later defeated Democrat Steve Dodd in the general election.
His arrest record became an issue in his 2004 race, again against Dodd, but he won by double digits. In his last campaign, he defeated his Democratic foe by more than 30 points.
Sullivan served in the state House before running for Congress.