Abstract: The efficiency of biodegradation of surface active agents by five bacteria strains was carried out on four anionic synthetic detergents found in the Nigerian Market. Biodegradation was carried by some strains of bacteria namely, Bacteroides fragilis, Peptostreptococcus, Clostridium botulinum, Staphylococcus aureus and Escherichia coli. Anaerobic and aerobic treatment systems were both effective in reducing the concentration of surfactants, however, anaerobic treatment generally produced the greatest removal. The results showed a removal rate of 99.9% by Bacteroides fragilis. The order of efficiency of the bacteria used was found to be: B. fragilis>C. botulinum>Peptostreptococcus sp., E. coli>S. aureus