An integrated process for converting a hydrocarbon feedstock having components boiling above about 100.degree. C. into steam cracked products is described. The process first involves passing the feedstock to a hydrotreating zone at a pressure in the range of from about 400 psig to about 1,250 psig to effect substantially complete decomposition of organic sulfur and/or nitrogen compounds. The product from the hydrotreating zone is passed to a steam cracking zone. Hydrogen and C.sub.1 -C.sub.4 hydrocarbons, steam cracked naphtha, steam cracked gas oil and steam cracked tar are recovered, where the amount of steam cracked tar produced is reduced by at least about 15 percent, basis the starting hydrocarbon feedstock which has not been subject to hydrotreating.