His body was found in Orient Gardens, off the Cliftonville Road, on Wednesday night.
Detectives Chief Inspector Eamonn Corrigan has appealed for anyone who was in the area between 7 pm and 10 pm on Wednesday, and has any information about the death, to contact detectives.
The men who have been detained by police are 26 and 28.
Nichola Mallon, an SDLP MLA for the area, tweeted that there was “shock and sadness across north Belfast at the death of a man and launch of a murder investigation by the PSNI”.
“Our thoughts are with his family. If anyone saw anything in and around Orient Gardens, no matter how small, please contact the police,” she added
There are no details at present about the deceased.