The incident happened at the property at Moffat Place, Gartness, in Airdrie at around 5pm on Tuesday.
The 39-year-old was attacked by four men who are yet to be identified in what was defined by the police as a ‘targeted attack.’
The men collectively struck the victim with hammers and he suffered injuries to his head.
As a result of the wounds he attained from the hammer attack, the 39 year-old required hospital treatment.
Detective Constable Paul James of Lanarkshire CID said: “Our investigations into this incident are ongoing and we would urge anyone with information or who saw any suspicious activity around the area on Tuesday to come forward.
“Our inquiries so far suggest this was a targeted attack with no risk to the wider public."