Abstract: Provided is apparatus suitable for continuous long-term monitoring of acoustic emissions, particularly from large structures such as pipelines. The apparatus comprises a plurality of detector-analyzer units coupled to a central control unit via a communications link. Each detector-analyzer unit comprises an acoustic detector, signal processing means, and a microprocessor. Preferably, the signal processing means comprises at least one signal conditioner, and at least one measuring circuit which provides digital output signals representing a set of emission parameters. The microprocessor preferably periodically receives and compares the digital output signal representing each of the emission parameters with the base values thereof, and provides a warning signal if a problem situation is perceived as a result of such comparison.