The invention relates to a monitoring system and method for accumulator banks including at least two pressure accumulators, the accumulator bank is coupled to a device and being adapted to provide a pressurized fluid into the device at pressure reductions in said device. The monitoring system comprises at least one sensor for detecting a chosen parameter in the accumulator bank at chosen intervals of time, and a recording unit for recording the sampled measured parameters, a storage device for storing predetermined characteristic information related to the pressure development in the accumulator bank during pressure reductions at the device and representing different numbers of active accumulators in the accumulator bank, and calculation means for comparing the recorded measured parameters with the stored characteristic information, and determining from this comparison the number of active accumulators in the accumulator bank.