CBOB is a common grade of gasoline produced by refiners in the US.

It gets its name from being a conventional grade of gasoline ("C") as opposed to a reformulated grade (such as RBOB) that has tighter environmental specifications. CBOB is a "BOB" (before oxygenate blending) because it is formulated for subsequent blending with 10% ethanol to form the final gasoline blend that is marketed to end users.