In the working area of the DCMR Environmental Protection Agency (EPA) an increasing number of people have registered complaints because of low frequency sound (LFS). A 'protocol of low frequency sound' for use in the Rotterdam-area has been developed. The purpose of the approach on LFS is threefold: (1) to offer the several organisations involved a handle to work with, in order to clarify the nature of the LFS complaints and structure them in a procedure; (2) to register their experiences with LFS; (3) to possibly develop a policy on LFS. Conclusions are as follows. (a) The indications lead us to assume that LFS is a growing problem. (b) If the source is not found directly there are complex factors contributing to the LFS-annoyance. (c) Those whose quality of life and health are threatened by LFS need help. (d) The system introduced is a good start. (e) Periodic modifications should lead to an improvement in efficiency. (f) A necessary condition is a consistent, well-equipped and well balanced team of people with experience in handling LFS-complaints. (g) To improve the approach it is worthwhile gathering