The overall aim of the present study was to extend the understanding of the Ombilin Basin oil shales by investigating the relationships between the nature of the basin sediments, the organic matter and the oil yield in the main oil shale bearing succession. This was based on integrating data from a combination of field mapping, mineralogical analysis and organic petrology techniques. It was hoped that anyrelationships established by the study would provide a more coherent framework for application to other oil shale successions, and a basis for better delineating quality trends and improving resource evaluations.