Police were called a Granville home where they discovered the man with serious injuries about 7.30pm on Saturday.
He was taken from the Blaxcell Street home by paramedics to Westmead Hospital where he was pronounced dead.
The woman was taken to the same hospital and her condition has been described as stable.
Police said they are investigating whether the pair’s injuries were the result of a domestic violence-related incident.
If you or someone you know needs help call 1800 RESPECT (1800 737 732)