The 26-year-old man was rushed to hospital after he was attacked on Balby Road earlier this afternoon.
A South Yorkshire Police spokesman said: “We received a call at 2:20pm today alerting us to reports of a stabbing on Balby Road in Doncaster.
“Upon officers’ arrival, a 26 year-old man was found with stab wounds to his chest, he has been taken to hospital by ambulance, where he remains in a critical condition.
“Balby Road and Sandford Road are both closed while officers conduct their enquiries."
Eyewitnesses at the scene have reported fire engines and ambulances and traffic being diverted.
Vehicles are being diverted away from Balby Road near to The Plough pub and along Greenfield Lane into Hexthorpe.
Anyone with information is asked to call 101 quoting incident number 404 of 28 September 2020.