Cyanide, cyanate, and thiocyanate, separately or in combination with other wastes, frequently are waste water problems. Several treatment methods are available for cyanide; some lack the desired efficiency, others are difficult to control, and all have high operating costs. Little information is available on the biological degradation of cyanates. Thiocyanate pollution has a long history but its characteristics commonly are misunderstood or ignored; lower treatment efficiency follows. Since the three anions are related in chemistry, in industry, and in waste control, a group comparison should bring out certain aspects of the individuals that might otherwise be unnoticed. The report discusses the authors' research in this area.