An experimental investigation of oil shale retorting is presented. The apparatus and operating conditions presented were specifically designed to simulate the in situ vertical fractured bed retorting process. The dependent retorting variables (oil yield, retorting rate, and bed weight loss) were investigated in terms of six process variables )gas content). Multiple linear regression analysis was used to determine the significance and rank of each variable. In addition, extensive temperature profile measurements were recorded and are presented from several of the more recent tests. Temperature profiles are illustrated graphically in two forms; as two dimensional time/ temperature profiles and as three dimensional thermo-response surfaces. A mathematical formulation of the experimental retort is presented and modeling results discussed.