An engineering scoping study was conducted at the US. Department of Energy's request to see if a feasible concept could be developed for using nuclear fusion heat to improve in situ extraction by retorting of underground oil shale. We found that a fusion heated, oxygen-free inert gas could be used for driving modified, in situ retorts at a higher yield, using lower grade shale and producing less environmental problems than present-day processes. It was also found to be economically attractive with return on investments of 20 to 30%. Fusion blanket technology required was found to be reasonable at hot gas delivery temperatures of ∼650°C (920 K). The scale of a fusion reactor at 2.8 GW(thermal) producing 45 000 Mg/day (335 000 barrel/day) was also found to be reasonable. Further development effort is recommended.