The invention relates to a fuel supply system for an internal combustion engine comprising:—a low pressure fuel pump (18);—a low pressure supply circuit (34) through which fuel is delivered by the low pressure pump (18) to one or several high pressure circuits (16), said low pressure supply circuit (34) comprising at least one delivery connection (36) for delivering fuel to the high pressure circuit(s) (16);—a pressure regulator (54) through which excess fuel from the low pressure supply circuit (34) is discharged through the pressure regulator (54) in a pump return circuit (56) which is fluidically connected to an input (20) of the low pressure pump (18) without passing through the fuel tank (14); characterized in that the pressure regulator (54) is located downstream of the delivery connection (36), and in that a fuel derivation circuit (60) is fluidically connected to the low pressure fuel supply circuit (34) downstream of the at least one delivery connection (36) to the high pressure circuit(s) and upstream of the pressure regulator (54).