You should only refuel with premiumgrade unleaded gasoline, as this avoids damaging the catalytic converter.
Flexible fuel vehicles, identifiable from the label inside the fuel filler flap, can be refueled with E85. For further information on flexible fuel, see "Fuel".
If engine running problems are apparent, have the cause checked immediately and repaired. Excess unburned fuel can otherwise enter the catalytic converter, leading to overheating and possibly causing a fire.

Use a filter when refueling from a fuel can.
Otherwise, the fuel lines and/or injection system could be blocked by particles from the fuel can.

Only refuel with premium-grade unleaded gasoline with a specified minimum octane number of 91 (average value of 96 RON/86 MON).

You will usually find information about the fuel grade on the pump. If you cannot find the label on the pump, ask the staff for assistance.

C 300 and C 300 Sport with automatic transmission: you can tell a flexible fuel vehicle by the label inside the fuel filler flap.

You can find more information under "Fuel", or by contacting an authorized Mercedes-Benz Service Center or visiting http://www.mbusa.com (USA only).