The aim of this study was to develop and to validate a methodology based on biomarker responses and residue analysis on the terrestrial lizard Podarcis sicula to assess the ecotoxicological effects associated with on-shore oil extraction. The oil treatment plant investigated is located in Val d'Agri (southern Italy). Italian wall lizards were sampled on four stations along a transect determined on the basis of prevailing winds downwind of the oil plant. Cytochrome P450 1A1 activities (EROD and BPMO), AChE activity, PAH bile metabolites and contaminant levels (PAHs and trace elements) were measured. Major results in the evaluation of toxicological impact of oil field activity in the Italian wall lizards were obtained for Cd, Hg, total and carcinogenic PAH levels, and PAH metabolites in bile. Results obtained validate, for the first time, P. sicula as a terrestrial bioindicator for the assessment of the toxicological impact of on-shore extraction activity.