The man, 37, was found in the doorway of the apartment block in which he lives in Liljeholmen, in the southern suburbs.
Following the discovery of the man, police sealed off parts of the stairwell and the injured man’s apartment, which is believed to be the scene of the attack.
The man was taken to the Karolinska University Hospital in Solna, where he underwent operations.
“He has very serious injuries – they are life-threatening,” said police spokeswoman Catharina Nordin.
The man remained in a critical condition on Tuesday morning. He was being cared for in the hospital’s intensive care unit, and has not yet spoken to police. The man is not previously known to police.
No arrests have yet been made in the case. Investigators on Monday evening went from door to door in the neighbourhood in search of witnesses, but without success. A forensic examination of the scene has been carried out; the results are expected on Tuesday.