The discharge of tannery effluents to different water bodies increase pollution because of heavyrnaccumulation of toxic compounds such as sulfur and nitrogen containing organic wastes, chromium,rnarsenic etc. Thitty-six strains of Sulfur Oxidizing Bacteria (SOB) belonging to sixteen genera werernisolated fi'om the three tannery ponds of a Tannery Waste Treatment system at Modjo. They wererncharacterized on the basis of their cultural, morphological, and physiological characters. The generarnwere Acidiphilium, Acromatium, Macromonas, Sulfolobus, Thermothrix, Thiobacilllls, Thiobacterium,rnThiomicrospira, Thiosphaera, Thiospira, Thiovullim Rhodobacfor, Rhodocyclus, Rhodomicrobillm,rnRhodopseudomonas, and Rhodosprillllm. Out of these isolates, twenty-one strains falling into twelverngenera were capable of denitrification. Bacterial enumeration based on MPN technique showed arnpopulation number between 1.2 x 103 and 1.1 x 106rn. The number of strains recovered from the differentrnponds varies such that twenty, sixteen, and nine strains were isolated fi'om AFP, SFP, and MP,rnrespectively. The dominant strains isolated from different pond systems were the genera Thiobacilllls (Srnstrains), Rhodopselldomonas, (4 strains), and Rhodomicrobiulll (3 strains). The most frequently isolatedrnstrains in the three different pond systems were Thiobacilllls (AUS9) and Rhodolllicl'obilllll (AU142).rnIsolated strains showed variation in growth on different media and some such as Acidiphiliulll (AUS);rnSlilfoloblis (AUl2); Thiobacillus (AUS9) Thiolllicrospira (AU62); Thiosphaera (AUS7)rnRhodolllicl'obilllll (AUl42, AU164, AUl76) failed to grow on denitrifYing medium but were capable ofrngrowing on nitrogen free (nit) medium. Most of the isolates were found to be slow growers reaching torntheir exponential stage between 4S-72 hours. In their spatial distribution, the anaerobic strains in AFPrnsystem and the aerobic isolates in the SFP and MP systems were found to be dominant.