Abstract: The present investigation is on evaluation of biodegradation potential of four species of hydrocarbonoclastic bacteria, B. megaterium, C. kutscheri, L. delbrueckii and P. aeruginosa and screening for plasmids. For biodegradation study, the strains were cultured in mineral salt medium with 0.1% of crude oil for seven days. Biodegradation results inferred that, P. aeruginosa showed 85.15% of crude oil degradation, followed by B. megaterium (78.5%), C. kutscheri (76.4%) and L. delbrueckii (71.6%). Strains were grown for 24 h in Luria-Bertani broth for plasmid study. Plasmid study revealed that, P. aeruginosa harbored two plasmids with molecular weight of 4.2 and 3.8 kb. The other strains namely L. delbrueckii, C. kutscheri and B. megaterium were found to have single plasmid with respective molecular weight of 3.8, 4.2 and 4.1 kb. Complete loss of biodegradation potential was observed when the plasmids of these strains cured with acridine orange.