Over recent days officers have been called out to thefts reports in Hackenthorpe, Intake, Stradbroke, Waterthorpe, Halfway, Beighton, Charnock, Mosborough, Birley, Gleadless Valley and Woodhouse.
Power tools were stolen from vans parked in Weakland Drive, Hackenthorpe; Hollybank Close, Intake; Oak Road Charnock; Stradbroke Road, Stradbroke; Harwood Drive, Waterthorpe; High Street, Mosborough; Spa Lane, Woodhouse and Oakes Park View, Gleadless Valley.
A vehicle was also targeted for power tools in Charnock Crescent, Charnock and another van was raided in Thornbridge Road, Birley, but it is not yet known what was stolen.
Officers are also investigating the theft of a van from Adastral Avenue, Charnock.
A South Yorkshire Police spokesman said: "If you own a van or know of anyone who does please feel free to alert owners of the current van crime.
"We appreciate tradespeople often leave vans insecure whilst working nearby as this is more convenient to them but this is an easy way for offenders to quickly take something without any signs of forced entry.
"Please park vans up to garage doors, walls or even other vehicles you own to restrict offenders access to the doors itself.
"Tips on keeping your commercial vehicle safe include fitting additional locks - especially to any side-sliding and rear doors.
"Always lock your vehicle, especially whilst on site, in a residential area or in the street.
"Fit an alarm. Insurance companies will often give a discount for properly installed and approved alarms.
"Never, leave personal documents or satnavs in the vehicle’s cab.
"It may not always be easy, but try not to leave tools or equipment in your vehicle overnight.
"Think about where you park. Prevent anyone getting into the back of the van by parking up against a wall, side-by-side or back to back with another vehicle.
"Always, try to park in a well-lit, open location. Park in areas covered by CCTV if possible.
"Keep your van keys safe while you are working - never leave them in your vehicle."