Background:  The major of this study was to isolate oil-degrading bacteria from soil contaminated with petroleum and examining the removal of hydrocarbons by these bacteria.

Methods: Oil-degrading colonies were purified from the samples obtained of around Ahvaz oil wells. Organic matter degradation was investigated with 1 g of crude oil in basal salt medium (BSM) as sole carbon source. The growth rate was determined through total protein assay and hydrocarbon consuming was measured through organic carbon oxidation and titration by dichromate as oxidizing agent.

Results: Two potential isolates named S1 and S2 strains were screened and identified as Planococcus and Pseudomonas aeruginosa. As results for S1 and S2 could degrade 80.86 and 65.6% of olive oil, 59.6 and 35.33 of crude oil, while 32 and 26.15 % of coal tar were consumed during 14 days incubation.

Conclusion: The results of this investigation showed these indigenous strains high capability to biodegradation at short time and are desirable alternatives for treatment of oil pollutants.