The road is closed near the junction with Oak Meadows after a man was discovered unconscious in the street.
Police have said that cordons will remain in place for most of the day while investigations continue, and people are advised to stay away from the area.
Officers have also cordoned off a section of Badsley Moor Lane in the town following reports of a large fight between two groups.
In a statement, a South Yorkshire Police spokesperson said: "Officers currently have a large section of Doncaster Road in Rotherham cordoned off close to the junction with Oak Meadows after the body of a man was discovered unconscious in the street.
"He was later pronounced dead at the scene.
"Enquiries are continuing at this time to determine how he came to be there. The cordon will remain in place for much of the day, and people are asked to please avoid the area while officers continue their work.
"In relation to another incident, officers also have a section of Badsley Moor Lane in Rotherham cordoned off near the junction with Victoria Avenue after reports of disorder between two groups taking place.
"Again, enquiries are continuing, and the cordon will remain in place as they do so. We also ask people to avoid this area too while this work continues. Updates will be provided through SYP’s social media channels when they become available."