48 Soil samples from a transect from low to highly hydrocarbon-contaminated soils were 49 collected around the Brazilian Antarctic Station Comandante Ferraz (EACF), located at 50 King George Island, Antarctica. Quantitative PCR (qPCR) analysis of bacterial 16S 51 rRNA genes, 16S rRNA gene (iTag) and shotgun metagenomic sequencing were used to 52 characterize microbial community structure and the potential for petroleum degradation 53 by indigenous microbes. Hydrocarbon contamination did not affect bacterial abundance 54 in EACF soils (bacterial 16S rRNA gene qPCR). However, analysis of 16S rRNA gene 55 sequences revealed a successive change in the microbial community along the pollution 56 gradient. Microbial richness and diversity decreased with the increase of hydrocarbon 57 concentration in EACF soils. The abundance of Cytophaga, Methyloversatilis, 58 Polaromonas and Williamsia were positively correlated (p-value = <0.05) with the 59 concentration of total petroleum hydrocarbons (TPH) and/or polycyclic aromatic 60 hydrocarbons (PAH). Annotation of metagenomic data revealed that the most abundant 61 hydrocarbon degradation pathway in EACF soils was related to alkyl derivative-PAH 62 degradation (mainly methylnaphthalenes) via the CYP450 enzyme family. The 63 abundance of genes related to nitrogen fixation increased in EACF soils as the 64 concentration of hydrocarbons increased. The results obtained here are valuable for the 65 future of bioremediation of petroleum hydrocarbon-contaminated soils in polar 66 environments.