Danny Ross Giles, 44, has been a suspect in the case for several years, but officials say they now have enough evidence to link him to the killings.
Giles is a registered sex offender and was already in custody at the Special Commitment Center on McNeil Island for a separate crime.
He has now been arrested for investigation of two counts of first-degree murder in the deaths of 22-year-old Tracey Brazzel and 26-year-old Patti Berry.
Brazzel was last seen leaving Kodiak Ron's Pub in Everett on May 26, 1995. Her body was never found, but detectives believe she was murdered by Giles.
Her car was found near her apartment complex with its passenger door window smashed out and a small spot of blood on the car door.
Patti Berry was reported missing on July 31, 1995. She was last seen leaving work at Honey's Adult Entertainment Club formerly located on Highway 99 near Lynnwood. According to detectives, her car had a low tire and she planned to look for a place to fill it with air before driving home.
A day later her car was found behind a convenience store in south Everett, near a car wash that also provided air. Detectives found the driver's window down and a lot of blood both inside and outside the car.
Berry's body was found the next week in a wooded area just south of the Everett Mall. She had been stabbed multiple times.
Snohomish County sheriff's spokeswoman Shari Ireton said both cases went cold until 2008, when investigators at the state crime lab matched DNA evidence from Berry's murder to Giles. In 2010, investigators matched DNA from Brazzel's home to Giles.
Detectives spent the next two years going over the evidence again, interviewing witnesses and following up on other leads to tie Giles to the killings.
"Even though it took 17 years, through the dedication and hard work of our detectives, we finally got our man," Snohomish County sheriff's Chief Kevin Prentiss said in a news release.
Giles is being transferred to the Snohomish County Jail and was expected to be held on $4 million bail.