Processes for the conversion of ethylene to valuable oxygen-containing products such as propanal, propanol, propionic acid, and alkyl propionates have been surveyed. The ethylene hydroformylation and carbonylation processes have been considered, and the state-of-the-art of technologies and promising lines of scientific research have been specified. The role of oxo processes as a way of the deep conversion of refinery off-gases to valuable petrochemicals has been defined.