Police said the victims, aged 21 and 24, were attacked at a takeaway on Elmbridge Parade, off Annandale Road in East Hull, at around 10.30pm on Sunday.
A Humberside Police spokesperson said: "The men reported that they were set upon by up to 10 youths as they were heading home after a night out in Hull.
"The assault has resulted in two young men sustaining serious facial injuries."
The offenders headed towards Preston Road after carrying out the attack on the city's Greatfield Estate.
Inspector Mark Peasgood, of East Hull Community Policing Team, said: “Anyone who knows anything about this incident should call us as a matter of urgency. These two young men were going about their business when they were assaulted and we want to find the people who did it."
Ins Peasgood said neighbourhood watch schemes had been set up over the past year to reduce crime and anti-social behaviour on the estate.
He added: "We have not received any reports of gangs of youths gathering in the area and if people are seeing this happen we want to know about it. If we don’t know about it we cannot do anything to deal with them.
"You can call us on 101 or speak to my officers on the ground or at the regular local police surgery at the Co-op."