DEERFIELD, Ill. — Walgreen Co. is turning over the operation of 56 Chicagoland in-store Healthcare Clinics to Advocate Health Care, the largest health system in Illinois.

Advocate will lease the space in the Walgreens stores to run the walk-in medical clinics. The clinics are set to be rebranded as Advocate Clinic at Walgreens and will reopen under Advocate’s aegis.

The move furthers Walgreens’ strategy of investing in its core business and expanding services to build a strong and viable model for future growth while developing deeper, more innovative approaches with health systems.

“Advocate shares our commitment to delivering extraordinary, personalized patient care, and is a nationally recognized health system that, like Walgreens, has been serving Chicagoland communities for more than 100 years,” Dr. Pat Carroll, chief medical officer for Walgreens Healthcare Clinics, said in a statement. “We believe this approach will help ensure a true continuum of care for patients and their providers. This is also an emphasis for our Walgreens-managed clinics, where we continue to make investments, such as a new EHR platform, to offer patient benefits through a variety of convenient care ­options.”

The retail clinics will function as part of Advocate’s network and will strengthen care coordination for patients, while also furthering overall convenience and access, the company said.

“Advocate Clinic at Walgreens expands Advocate’s care delivery locations to provide more options for patients and meet the needs of consumers in an evolving health care environment,” said Dr. Lee Sacks, Advocate’s chief medical officer and executive vice ­president.