A man in his 30s has died suddenly in Banbridge.
Police attended the scene at a house in the Golf Terrace area on Thursday night.
The man has been named locally as Gavin Bradley.
A post-mortem examination will take place in due course.
In a separate incident, a 29-year-old man died suddenly in Portadown. He passed away in what locals described as tragic circumstances in the Hartfield Avenue area of the town.
He was named locally as Alan McCreery, a former Craigavon Senior High School pupil.
Police said they were not treating his death as suspicious.
Upper Bann DUP MLA Carla Lockhart said the local community was in shock.
"It is such a sad situation that a young man's life has ended in its prime," she added. "This is the second sudden death in the constituency in two days and to that end the community is coming to terms with the fact that two young lives have been lost.
"With regards to the Banbridge death, I have on a number of occasions contacted the PSNI and the Housing Executive concerning some of the alleged activity in this area. I am therefore calling on the authorities to take action."