Seven fire engines and a turntable ladder are currently at the scene of a huge blaze on Chesterfield Road, Heeley, which was reported to emergency services at around 10.30am today.
Police officers and paramedics were also deployed to the scene and an air ambulance was scrambled.
One casualty was taken to hospital by ambulance but no other details, including their condition, has yet been released.
South Yorkshire Fire and Rescue said the blaze was 'serious’ and the casualty was ‘brought out’ of the burning building, which involves Milan’s Pizza takeaway shop and flats above.
The fire service said: “Crews are searching the premises for further casualties.
“The fire is thought to have started at a takeaway which also has residential flats above.
“An investigation into the cause will begin once the fire has been extinguished.”