Emergency services were called to a home on Warung Street on Monday night, following reports of a concern for welfare.
An 18-year-old man was assisted by witnesses before paramedics attended, however, he died at the scene.
Bankstown Police established a crime scene, which was forensically examined.
Inquiries are continuing.
Police investigating Yagoona death
POLICE investigating the death of an 18-year-old man in Yagoona last night arrested a 52-year-old woman before she was taken to Bankstown Hospital for assessment.