A method of monitoring vibratory phenomena that occur in an aviation gas turbine engine in operation includes establishing a frequency spectrum of a vibratory signal representative of the operating state of the engine and of its components; using a plurality of vibratory signatures, each corresponding to a vibratory phenomenon that occurs during operation of aeroengines of the same type as the engine being monitored and originating from a defect in or an abnormal operation of a component of the engines; identifying, in the spectrum, the points of curves that match mathematical functions, each defining a vibratory signature; and for each identified curve corresponding to a defect of engine components, analyzing the amplitude associated with the points of the curve relative to predefined amplitude values corresponding to a degree of severity of the defect; and as a result of an amplitude value being exceeded or an abnormal operation being detected, issuing a message associated with the vibratory signature.