A hydroprocessing process includes two cocurrent flow liquid reaction stages and one vapor stage, in which feed components are catalytically hydroprocessed by reacting with hydrogen. The liquid stages both produce a liquid and a hydrogen-rich vapor effluent, with most of the hydroprocessing accomplished in the first stage. The first stage vapor is also hydroprocessed. The hydroprocessed vapor and second stage vapor are cooled to condense and recover additional product liquid and produce an uncondensed hydrogen-rich vapor. After cleanup to remove contaminants, the hydrogen-rich vapor is recycled back into the first stage as treat gas. Fresh hydrogen is introduced into the second stage. This is useful for hydrotreating heteroatom-containing hydrocarbons.