Start of Main Content

How many ambulatory surgery centers are in the U.S.?


Ambulatory surgery centers (ASCs) are outpatient facilities that offer an alternative to hospitals for patients undergoing routine surgical procedures. Like hospitals, ASCs are regulated by state and government agencies to ensure patient safety. Many surgery centers focus on a single specialty, such as plastic surgery, orthopedics, or neurology.

Over the last several years, there has been a shift in care from hospital facilities to more surgical procedures taking place at outpatient facilities like ASCs.

What type of procedures are performed at ASCs?

The most common types of surgical procedures performed at ASCs include:

  • Cataract removal
  • Colonoscopy
  • Biopsy
  • Knee replacement
  • Hip replacement

How many ASCs are there in the U.S.?

According to the Definitive Healthcare SurgeryCenterView product, there are nearly 9,100 active ASCs in the U.S.

We use a variety of sources to maintain our ASC data including the Provider of Service (POS) File, CMS’ Medicare Ambulatory Surgery Center Limited Data Set (LDS), CMS Ambulatory Surgery Center Compare, and proprietary research.

How many operating rooms does a typical ASC have?

ASCs may be small and have a single operating room (OR), while the largest ASCs have hundreds of ORs. Based on data from more than 5,500 facilities, on average, ASCs have 3 ORs.

How are ASCs different from hospital outpatient centers?

The primary difference between hospital outpatient departments (HOPDs) and ASCs is that hospitals offer inpatient services and overnight observation on site. This is convenient in the event of surgical complications, as patients don’t have to wait for an emergency transport service. 

Though both facility types see low infection rates, surgery centers are also associated with lower rates of surgical site infections. Because patients recover at home, they are less likely to be exposed to bacteria and viruses from providers and other patients.

Another reason patients opt for surgery centers over hospitals is the cost. Surgery centers are often focused on a single specialty, do not include an option for overnight observation, and have lower overhead costs than hospitals, resulting in savings that are passed on to patients. 

We published an infographic further detailing the differences between ASCs and hospital outpatient centers, including procedure claim volumes, clinical outcomes, reimbursement rates, and more. 

When patients choose an ASC over a hospital

Though outpatient surgery centers offer convenient and often lower-cost alternatives to HOPDs, a limited number of procedures and specialties are suitable for such a setting. Every year, CMS releases its inpatient-only list: procedures that will only be reimbursed in an inpatient setting under the Hospital Outpatient Prospective Payment System due to concerns about patient safety and care outcomes. It’s important that all types of facilities monitor this list in order to adjust their strategies and plan accordingly.

Some specialties, like pain management and ophthalmology, are ideally suited to ASCs due to their ability to see large volumes of patients in a short period of time, ensuring profitability. Since 2015, the Medicare Payment Advisory Commission (MedPAC) has suggested that CMS reduce HOPD reimbursement for certain outpatient visits to encourage the shift to ASCs, where patient volumes could be more steadily maintained, and HCP expectations met.

Surgery centers are also the facility of choice for patients who have few or no comorbidities. Patients likely to experience complications would probably be referred to hospital outpatient centers, where overnight monitoring and extensive specialty services are available in the event of an unforeseen circumstance.

While both ASCs and HOPDs are high-quality options for patients in need of surgical procedures, individuals may have a preference based on medical history, accessibility, cost, and other factors.

Learn more

To learn more about trends in outpatient surgery, download our white paper on the shifting point of care from hospitals to ambulatory surgery centers

And if you need even more insights, start a free trial now and get access to the latest healthcare commercial intelligence on hospitals, physicians, and other healthcare providers.

Maggy Bobek Tieché

About the Author

Maggy Bobek Tieché

Maggy Bobek Tieché has worked with healthcare data for nearly 18 years. Her positions include roles in product management and custom reporting, working with life science,…

Author profile