Some hazards posed by the operation of hydraulic systems, connected with low-frequency vibrations and noise are presented. Special attention is focused on infrasounds. The sources of low-frequency vibrations and noise and the ways of reducing them are indicated. Moreover, this paper deals with the effects of external mechanical vibrations on hydraulic valves. An original solution ensuring the effective reduction of vibrations and noise in a wide frequency range, i.e. a wide-band damper of pressure fluctuations, also performing the function of an acoustic filter, is proposed. The results of preliminary experimental tests of simple vibration insulators are reported. The effectiveness of the damper has been confirmed by the results of laboratory tests and tests carried out on engineering machines working in real conditions. Problems relating to the noise emitted into the environment by machines equipped with hydraulic systems are covered by Polish and EU standards and directives, e.g. PN-ISO 9612:2004, Directive No. 2000/14/EC and Directive No. 98/37/WE.