Hydrocarbon degrading microorganisms play a major role in the environment. In the present study crude oil degrading fungal strain Aspergillus niger was isolated from oil contaminated soil near crude oil production well (Lingala) Andhra Pradesh. The rate of reduction in some petroleum hydrocarbon fractions, such as n-alkanes, aromatics, nitrogen, sulfur and oxygen (NSO)-containing compounds and polycyclic aromatic hydrocarbons (PAHs), were monitored by means of gas chromatography. The nC 17 /Pristine and n C 18 /Phytane ratios, extrapolated from the GC profiles decreased from the initial value of 2.510 and 7.289 to 0.132 and 0.474 respectively at day 60.