By Cecilia Butini

Fresenius SE & Co. KGaA on Thursday said Fresenius Helios, its hospital-operator division, is acquiring three hospitals and four medical care centers in western Germany from the Malteser humanitarian aid organization.

The companies decided not to disclose the financial terms of the acquisition, Fresenius said.

The German health-care company said that Fresenius Helios expects the acquisition to be finalized in the fourth quarter of 2020, pending approval from German antitrust authorities.

The acquisition will be accretive to group earnings starting in 2021, Fresenius said.

The facilities at the center of the deal--which are located in the cities of Duisburg and Krefeld--have a total of 870 beds and posted roughly 160 million euros ($189.4 million) in sales last year, the company said.

The hospitals in Duisburg cover various specialty areas like general surgery, internal medicine, geriatrics, and offer a special focus in hematological oncology, Fresenius said.

The facility in Krefeld offers treatments in oral and maxillofacial surgery and internal medicine, the company said.

Write to Cecilia Butini at cecilia.butini@wsj.com