Healthcare provider Kaiser Permanente has signed a definitive agreement to acquire Seattle-based Group Health Cooperative, the companies announced today. Once the deal is final, Kaiser Permanente will gain approximately 590,000 new members.

“This agreement is a natural extension of our long, successful working relationship with Group Health and it provides us with the opportunity to expand access to high-quality, affordable care and coverage,” Bernard J. Tyson, Kaiser Foundation Health Plan and Hospitals chairman and CEO, said in a statement. “Kaiser Permanente and Group Health Cooperative are a natural fit. The opportunity to unite will allow us to best serve the current and future needs of our members, customers and employees. We look forward to welcoming the people of Group Health Cooperative into the Kaiser Permanente family.”

According to both companies, there will be no immediate changes to Group Health’s coverage or care. The company will be fully integrated into Kaiser Permanente and become its eighth official region of coverage, joining Colorado, Georgia, Hawaii, Mid-Atlantic States, Northern California, Northwest (Oregon, Southern Washington), and Southern California.

"For those of you who have counted on Group Health to provide you with amazing physicians and clinical teams, and the coverage your family needs, you will continue to receive the best care and coverage available," Steve Tarnoff, MD, Group Health Physicians president, said in the same statement.