Abstract: Soil microbial assortment is affected by hydrocarbon perturbation, thus selective enrichment of hydrocarbon degraders occurs. Hydrocarbons interact with the terrestrial ecosystem and soil microorganisms shaping the fate of the contaminants relative to their chemical nature and microbial degradative capabilities, respectively. Microbial methods for monitoring bioremediation of hydrocarbons include chemical, biochemical and microbiological molecular indices that measure rates of microbial activities to show that in the end the target goal of pollutant reduction to a safe and acceptable level. While it is broadly accepted that bacteria and fungi are chief mediators in hydrocarbon degradation, bacteria have been revealed to be more versatile than fungi and therefore may play a greater role during biodegradation of hydrocarbons. Biodegradation via algae, yeast and protozoans are also found important in degrading wide range of these petroleum hydrocarbons. Microbial degradation by Arthrobacter, Mycobacterium, Pseudomonas, Rhodococcus, Aspergillus, Penicillium, Chlorella, Cyanobacteria and Candida can be considered as a key component in the cleanup strategy for hydrocarbon remediation. This brief review will inspect hydrocarbon degradation by microorganisms under different ecosystems.