The 30-year-old was treated by paramedics after being found injured in Batemoor Close, Batemoor, before being transported to accident and emergency at the Northern General Hospital.
An air ambulance landed at the scene but it is believed that the man was driven to hospital under a police escort.
Batemoor Close is sealed off and under police guard as detectives investigate the circumstances surrounding the stabbing.
A South Yorkshire Police spokeswoman said: "A report was received at around 12.25pm today that a man had suffered suspected stab wounds in the Batemoor area of Sheffield.
"Officers are currently in attendance at the scene on Batemoor Close.
"The 30-year-old man has been transported to hospital where his condition at this time is believed to be life threatening."
Anyone with information should call South Yorkshire Police on 101.