At around 11.40pm a 42-year-old local man was walking home along Bondgate when he was attacked from behind just past the Unicorn public house. He fell to the ground and was kicked several times until he lost consciousness.
He suffered a broken nose and eye socket in the incident during which his black rucksack was stolen.
Approximately 30 minutes later a 32-year-old man was making his way home across a field behind Scott Road surgery. As he approached the entrance to Millgate he heard people running behind him. He turned to face them and a man asked him his name before punching him in the face. He fell to the ground and was kicked unconscious.
During the attack his wallet and mobile phone were taken.
Police believe that the incidents may be linked.
Detective Constable Amanda Bostwick, of Selby CID, said: "These were violent unprovoked assaults and I am appealing for any witnesses to come forward.
"I would particularly like to speak to anyone who may have seen two white men and a woman in the area the incidents took place. They were all wearing black clothing and one of them may have been carrying a black rucksack.
"If anyone has information about either incident please contact the police or Crimestoppers immediately."
Anyone with any information that could help the police with their enquiries should contact DC Amanda Bostwick or DC Lee Maeer, of Selby CID on 0845 60 60 24 7.
A 17-year-old youth from Selby has been arrested in connection with both incidents and released on bail as enquiries continue.
