An integrated hydrotreating and steam pyrolysis process for the direct processing of a crude oil is provided to produce olefinic and aromatic petrochemicals. Crude oil and hydrogen are charged to a hydroprocessing zone operating under conditions effective to produce a hydroprocessed effluent reduced having a reduced content of contaminants, an increased paraffinicity, reduced Bureau of Mines Correlation Index, and an increased American Petroleum Institute gravity. Hydroprocessed effluent is thermally cracked in the presence of steam to produce a mixed product stream, which is separated. Hydrogen from the mixed product stream is purified and recycled to the hydroprocessing zone, and olefins and aromatics are recovered from the separated mixed product stream.