The 20-year-old was rushed to Glasgow Royal Infirmary in the early hours of this morning.
Officers were called to the Gallowgate after reports a man being found injured in the street at around 1am.
His injuries are not thought to be life-threatening and medical staff described his condition as "stable".
Detectives closed the Gallowgate, between Little Dovehill and Ross Street, while investigations were carried out.
A Police Scotland spokeswoman said: "Officers received a report of man being assaulted in the Gallowgate, Glasgow, at around 1.20am today.
"The 20-year-old was taken to Glasgow Royal Infirmary.
"Inquiries are ongoing."
It is understood officers are following a positive line of enquiry.
The Gallowgate re-opened shortly after 4.30 am today.