The present invention relates to a method of estimating, for a petroleum feedstock, values representative of the sulfur and carbon distributions in atmospheric and vacuum distillation residues, and a value representative of the sulfur content in coke. According to the method, the following stages are carried out: from a feedstock sample, measuring at least the Rock-Eval parameters S2b, SulfS2b, RC, Sulfoxy using a Rock-Eval device comprising a sulfur measurement module, deducing from the measurements of these Rock-Eval parameters the values of the sulfur and carbon distributions (SPHF, SCOKE, CPHF, CCOKE) in the distillation residues, and a sulfur content in relation to the carbon content in the coke.