In this study, we describe the development of microbial inoculants for the bioremediation of hydrocarbon-contaminated soils through the enrichment of hydrocarbonoclastic populations in municipal solid waste compost (MSWC). Respirometric analyses were performed along with quantification of total heterotrophic bacteria and ester-linked fatty acid methyl ester (EL-FAME) profiling of the microbial communities of the inoculants. CO₂-emission rate increased sharply when the compost received application of water plus gasoline or diesel. After 8 (compost diesel) and 12 days (compost gasoline), we observed a significant increase in the number of heterotrophic bacteria. In inoculants receiving gasoline, FAME markers of fungi predominated throughout the incubation period (18 days). By the end of the incubation period, an increase in FAMEmarker for gram-positive bacteria and a decrease for gram-negative bacteria and actinobacteria were observed. In biodegradation trials (data not shown), the inoculants were very efficient, removing over 99% of hydrocarbons from a heavy soil (73% clay) contaminated with either diesel or gasoline (17,000 mg·Kg^﹣1 and 15,000 mg·Kg^﹣1, respectively). Inoculants based on MSWC enriched in hydrocarbonoclastic microorganisms may be an effective alternative to improve bioremediation in hydrocarbon-contaminated soils.