The distribution of ring-C monoaromatic and triaromatic steroid hydrocarbons of about fifty crude oils and sediments of various origins and ages were studied in order to test their validity as geochemical source and maturity parameters. Three ratios appeared to be useful maturity parameters, . A/B cis to trans isomers in non-rearranged monoaromatics, mono/triaromatics and shortvs long-chain homologues. Four other variations may be considered as source parameters depending upon lithology or other palaeo-environmental conditions, . rearranged vs non-rearranged monoaromatics, 5β/5α -methyl rearranged monoaromatics, carbon number distribution and occurrence of a yet unknown series of methylated triaromatic steroids. 5α-Methyl rearranged monoaromatics seem to be particularly important in anhydrites from sabkha environments. Recent identification of most aromatic steroid constituents occurring in geological samples confers on this class of compounds an increasing value as correlation parameters in geochemical studies.