Between 1935 and 1940, Clinic doctors tried a new concept in health care " a prepaid medical care plan. For $18 a year, a person could have all their medical, surgical, and hospital needs met. The plan cost $24 for two people, $30 for three people and $32 for four people. There were $34 and $38 plans to cover an entire family. In the first year 1,000 families enrolled in the prepaid plan and 1500 families were enrolled in the first 18 months. The County Medical Society disapproved of this "radical" plan, so they threatened to throw out the Clinic doctors and have their hospital privileges withdrawn. Although the county commissioners stood behind the Clinic doctors, the plan was discontinued in 1939.

During World War II and immediately after, all of the Clinic physicians except Dr. Haskell and Dr. John Darst went to war. These remaining physicians took care of all the patients until the other physicians returned from war.

Beginning in 1947, the Clinic added a surgeon, Dr. Eugene Wiege. Dr. Marsh, an eye, ear, nose, and throat specialist used the third floor of the Clinic to fit eyeglasses and remove tonsils, adenoids, and teeth. During the early 1950s, the Clinic outgrew its original building and moved to larger quarters, directly east of the current facility, where a series of new specialties were added.

In 1960 the Clinic began the process of centralizing all patient medical records. During the early 1960s, the first computer system was installed, with the main computer at the Greeley National Bank and terminals in the Clinic.

Construction of the present building began in 1972. Two floors were built, with plans to add two more floors later. The new Clinic provided expanded X-ray and laboratory services as well as a larger medical record area. This decade was noted for the large number of new specialties added to the Clinic including gastroenterology, dermatology, genitourinary surgery, pulmonary disease, oral surgery, and oncology. With these additions, the Greeley Medical Clinic became a major medical center in Northern Colorado.

In April 1985, the Greeley Clinic doctors joined with the nearby Medical Group of Greeley to become the Greeley Medical Clinic. Combining seemed a natural step in evolution for both groups. The Medical Group also provided multi-specialty care to the community, was located only two blocks from the Clinic, and like the Clinic, had outgrown its facilities.

During the 1980s, new medical specialties including allergy, cardiology, nephrology, ophthalmology, preventive and occupational medicine, rheumatology, and sports medicine were added to the Clinic. Laboratory and X-ray facilities were expanded and a mammography unit was installed. Related services such as audiology, nutrition, and gerontology were now available to patients.

In November 1987, the addition of two floors, plus renovation of the basement and first two floors was completed. The Urgent Care facility was also added at this time. The renovation increased the building's capacity to 55 doctors.

In 1990 Greeley Medical Clinic affiliated with a physician practice management company called PhyCor, out of Nashville, Tennessee. Patients still knew the clinic as Greeley Medical Clinic, but for business dealings the new name was PhyCor of Greeley. GMC was affiliated with PhyCor until 2000.

In the mid-1990s, Harmony Medical Center was opened in Fort Collins with 10 providers in family practice and obstetrics/gynecology, as well as a daytime Urgent Care department to handle day-of-service patient care for overflow and walk-ins.

In 1997, Eaton Family Practice became a satellite clinic, and Parkview Family Practice and Greeley Physicians for Women were added. In late 1996, construction began on an addition to the east side of the main campus building for a new Diagnostic Imaging Center, which opened in January of 1998. The Center provides services for Magnetic Resonance Imaging (MRIs), mammograms, ultrasounds, bone density, X-rays, and CT scans.

In 2002, renovation and redesign of the main campus began, including the public restrooms, reception areas, and pharmacy. Loveland Oncology moved to the new Loveland Cancer Center. Peakview Medical Center opened in west Greeley with pediatrics, family practice, and rehabilitation services; added to the Peakview roster within three years were ENT, audiology, and dermatology. By 2004 GMC added pulmonology, a Loveland rheumatology satellite clinic, and Urgent Care West. In August of 2004 the Greeley GMC oncology department moved into the state-of-the-art Cancer Institute in the NCMC building, and in 2007 a new sleep lab was added at Mountain Vista Office Park.

Recent years have brought several additional changes to GMC. Medical Clinic at Centerra, PC was opened at the MCR North Medical Office Building in Loveland in early 2009. The most recent addition was Windsor Medical Center, as of March 2010. Today Greeley Medical Clinic has more than 80 providers and over 300 employees, and serves patients in northern and eastern Colorado, western Nebraska, and southeastern Wyoming.

Effective July 11, 2010, Greeley Medical Clinic joined Poudre Valley Medical Group, which is part of the Poudre Valley Health System. Our patients are able to continue seeing our providers in convenient locations throughout Northern Colorado, and may continue to choose care at either North Colorado Medical Center or Medical Center of the Rockies.