The problems caused by the formation of sulfide within sewerage systems are briefly reviewed. The mechanism by which the hydrogen sulfide is produced within sewers and the procedures for controlling its production are briefly outlined. In order to design effectively for sulfide control a reliable means of predicting the rate of sulfide production is desirable. The different procedures which have been developed in Australia, the United Kingdom and the U.S.A. (i.e. the equations developed respectively by Thistlethwayte, Boon and Lister, and Pomeroy) are, however based on empirical correlations of experimental data, and hold over a limited range of operating conditions. These procedures are also known to be unreliable. The desirability of replacing the present procedures by a more rational approach is demonstrated. A major advantage of the new approach, which is based upon a chemical engineering analysis of the mass transport and biochemical processes which occur, is that, whereas the previous procedures were developed essentially for domestic sewage, the more rational approach can be applied to sewage containing a high proportion of industrial effluent.