This manual was prepared jointly by the IEF and its Jodi oil partners : APEC, Eurostat, IEA, OLADE, OPEC and UNSD. The objective is to help data collectors and users understand the methodology and definitions used in the Jodi oil questionnaire. This manual will help data collectors to conduct basic verification of data, avoid common reporting errors and share examples of best practices. Moreover it was deemed useful to supply some background information on how oil is produced, refined, etc.