At about 4.50 pm on Thursday a 37-year-old man was assaulted while sitting in the bus stop next to Goldie Park in Glasgow Street.
The victim appears to have been struck on the head by a man and then attacked on the ground.
The suspect is described as a white male, aged 35 to 45, between 5 foot 8 and 5 foot 10 in height, of medium build with short/medium length dark and grey speckled hair.
He was wearing a dark coloured jacket and navy blue coloured denim jeans.
Following the assault the suspect walked off in the direction of Goldie Park.
As a result of the assault the victim has suffered serious injuries, including a collapsed lung, and currently remains in a serious condition within Dumfries and Galloway Royal Infirmary.
DC Rowan Buckly of Dumfries CID said: “I know this is a busy route in and out of town and I believe a number of people will have driven past this bus shelter at the time of the assault.
“Officers are currently checking CCTV in the area and carrying out door-to-door enquiries.
“However, I would appeal to anyone who was in the area who may have seen the attack, or who has any information that will assist officers with their investigation, to contact Dumfries Police Office via 101 quoting incident number PDG0095870417 or if they want to remain anonymous, through Crimestoppers on 0800 555 111.”