The incident took place at a house in Polo Gardens, Troon, on Friday evening.
A 38-year-old man was held in London on Saturday, and police officers from Strathclyde travelled down to bring him back to Scotland. He is due at Ayr Sheriff Court today.
The woman who died was named locally as 63-year-old Ann Morris. Her husband Fred suffered serious head and chest injuries and was taken to Crosshouse Hospital, Kilmarnock, where he was said to be "serious but stable".
A post mortem will be held to determine the cause of Mrs Morris's death.