A method is described for detecting aging effects in components of an optical fiber amplifier wherein a broadband signal is amplified by means of a pump source in conjunction with at least one amplifying fiber. Input and output powers or, as the case may be, photon flows are determined at the input of the first amplifying fiber and at the output of the last amplifying fiber. Photon balancing from which an effective pump power of the pump source is calculated taking account of the characteristics of components of the optical amplifier at the beginning of life is calculated is carried out using the input and output powers or, as the case may be, photon flows in the case of a present operating status. Conclusions can be drawn about the aging of components in the optical fiber amplifier depending on the nature of the difference between the current and effective pump powers. An associated monitoring device is presented for implementing the method according to the invention.