Abstract: Electrical Resistivity Tomography (ERT) and vertical electrical resistivity sounding (VES) surveys were jointly carried out to characterize a petroleum hydrocarbon impacted site. Both surveys were carried out after 14 months of spill and repeated after 28 months of the first survey (42 months of spill) using same traverse and electrode positions. The objective is to characterize the electrical structure and determine the lateral and depth extensions of the hydrocarbon contaminated horizons in soil and groundwater. Results revealed that the soil and groundwater in the investigated site have been contaminated by petroleum hydrocarbon, with a characteristic low resistivity anomaly associated with microbial degradation over time. The minimal depth of impact is approximately 13 m below the groundwater table, with a lateral spread in excess of 100 m on either side of the spill point parallel to the pipeline right of way. The contaminant strength is higher for season one than two, since it is a recent spill. Results also show that soil degradation arising from petroleum hydrocarbon contamination may result to changes in bulk density of the impacted soils. This may likely affect the compressibility and surface hydrogeology of the soils and therefore, alter the infiltration rate and direction of groundwater flow. This way, groundwater recharge from surface precipitation in the investigated site could be adversely affected.