This research was designed to investigate the relationship between audit risk and the conduct of the audit engagement in the specific context of an oil and gas audit. Because reserve estimates are in the financial reports of oil and gas entities (in the depreciation, depletion and amortization calculation, the limitation on capitalized costs for companies using the full-cost method, and the required supplementary disclosure for companies subject to Securities and Exchange Commission requirements) and because the reserve estimation process is considerably affected by numerous factors, there is a chance that a material error could be incorporated into the financial statement representations with which the auditor is associated. The objective of the research was to (1) identify conditions which are important in an assessment of audit risk in associating with reserve estimates, and (2) determine the impact of some of these conditions on the conduct of the audit.