Chemical analyses and tests, petrographic data, hydroretoring tests by thermobalance, and extractions of kerogen by tetralin have been obtained on a suite of eight Eastern oil shales, and except for petrography, on a Colorado oil shale. The organic carbon-hydrogen ratios of the Eastern oil shales ranged from 10.5 to 13.6, compared to 8.36 on the Colorado shale. The petrographic data indicated that the differences among the Eastern oil shales arise mostly from differences in their content of vitrinite. Organic carbon conversion, both to liquid and total, in hydroretorting correlates to some extent with extraction of kerogen by tetralin. Conversion decreases with increase of organic carbon-hydrogen ratio. The scatter of results, however, indicates that additional or different parameters are required for satisfactory correlations of hydroretorting yield. With the exception of one shale, organic carbon conversion by tetralin correlates well with organic carbon-hydrogen ratio.