The $220 million hospital includes Kaiser's Sunset Medical Office that opened in 1987 on the west side of the Portland metropolitan area.

Kaiser Permanente broke ground on their Sunset Medical Office on 50 acres (20 ha) in what was then unincorporated Washington County in August 1986.

[1][2] The facility, a 41,000-square-foot (3,800 m2) two-story brick building designed by Zimmer Gunsul Frasca Partnership, was built at a cost of $5.2 million and opened in 1987.

[8] Kaiser would also be responsible for some infrastructure improvements in the Tanasbourne area to mitigate the increased traffic generated by the hospital complex.

[15][16][17] On June 17, 2009, construction began with a groundbreaking ceremony attended by local dignitaries including Hillsboro mayor Jerry Willey and Oregon Governor Ted Kulongoski.

[16] The designs and artwork incorporate modern theories of creating an environment that is pleasing to assist in the healing process, which includes an exterior plaza that can host a farmer's market.

[26] Certified as LEED Gold, the medical center's green features include water retention tanks, wood composite insulation, and renewable energy, among others, at the $344 million hospital.

[27] Unlike many California-based Kaiser facilities, the Westside Medical Center has a brick-and-glass exterior, and a more extensive waterproofing system underground.

[20] The main hospital building is in the middle portion of the southern half of the campus, with the first patient tower to the west along 194th Terrace.