Satbir (50) and his cousins Raj Kumar (35) and Balraj (30) were killed and one other was injured in a clash between two families.
Amarjit, who suffered injuries, was taken to district hospital from where he was referred to PGI Rohtak, police said.
After a heated exchange between members of two families they attacked each other with sharp edged weapons, they said.
A case has been registered and a search hunt launched to arrest the five accused, according to police.