Police called after reports of a domestic incident in the Ely area.
South Wales Police were called to reports of a domestic incident in Lon-Yr-Efail, Caerau, Ely, at around eight o'clock last night
Despite the efforts of the emergency services, a 56-year-old man died at the scene.
An 18-year-old man has been arrested on suspicion of murder and is currently in police custody.
A statement form South Wales Police said:
"The street is currently cordoned off and the local community’s ongoing support while investigations continue, is appreciated."
Anyone with information about the incident who has yet to speak to police is asked to contact 101, quoting occurrence 1900214801.