A method for detecting and localizing a fuel leakage in the engine of a multi-engine aircraft consisting in determining a fuel consumption for each aircraft engine, in comparing the consumption of each engine with the other aircraft engines, in determining the engine exhibiting the greater fuel consumption ratio, in determining the excess consumption ratio of the aforementioned engine with respect to the other engines, in checking whether the excessive consumption is caused by a leakage and in triggering an alarm if the step is checked. A system for detecting and localizing a fuel leakage in the engine of a multi-engine aircraft including an airborne computer for carrying out the aforementioned method is also disclosed.