Rafael Castillo, 56, was taken into custody in Reseda around 10 p.m. Tuesday, Whittier police said.
Authorities said based on information gathered during the investigation, Castillo was charged with murder.
The woman, whose identity has not been released, was found dead at an apartment complex in the 11700 block of Floral Avenue Tuesday morning.
The cause of the woman's death was not immediately known, but authorities are describing the incident as suspicious.
Investigators said the woman and Castillo knew each other -- but didn't elaborate.
Castillo is being held at the Whittier Police Department Jail on $1 million bond. He is set to be arraigned on Thursday.
Anyone with information about this case was asked to call Whittier police at (562) 567-9283 or L.A. Regional Crime Stoppers at 800-222-TIPS (8477).