A 70-year-old man will appear in the Zeerust Magistrate's Court on murder charges on Monday, North West police said.
Captain Amanda Funani said he was arrested on Saturday following the murder of Jean Rantsie, 52, whose partially decomposed body was discovered under a bridge.
"The suspect is believed to be Rantsie's boyfriend and they allegedly had an argument shortly before the victim disappeared."
Her body was discovered on Friday by a passer-by on the old Koster Road, close to Zeerust.
Rantsie was assaulted, hit with a rock on her head, and possibly raped before being killed. She left her home at Quariefontein farm on Wednesday, and did not tell her family where she was going.