A combined process for treating heavy hydrocarbon feedstocks, such as resids that minimizes coke production and maximizes naphtha production, comprising the steps of thermally treating the feedstocks, in the absence of an added catalyst and either with or without hydrogen and steam, at a temperature of at least about 750.degree. F. (399.degree. C.) and under a pressure greater than about 400 psig to create significant chemical transformations without causing phase separation and consequent formation of sludge or a coke deposit; topping the thermally treated product to produce a distillate fraction and a bottoms fraction; coking the bottom fraction to produce gas, liquid products, and coke; and finally catalytically cracking the combined distillate fraction and liquid products to recover gas, gasoline, and light distillate products.