A process is described for producing olefins from a vapor product stream from an oxygenate to olefin conversion reaction, the vapor product stream comprising C.sub.2 to C.sub.4 olefins, C.sub.5+ hydrocarbons, at least one oxygenate and water. In the process, the vapor product stream is cooled to remove water therefrom and produce a first vapor effluent stream. The first vapor effluent stream is then cooled and compressed to produce a condensed liquid effluent stream comprising C.sub.5+ hydrocarbons and at least one oxygenate, and a residual vapor effluent stream comprising C.sub.2 to C.sub.4 olefins. At least part of the condensed liquid effluent stream is contacted with a liquid water-containing stream in a liquid-liquid contacting device to at least partly separate said condensed liquid effluent stream, or portion thereof, into an aqueous phase rich in said at least one oxygenate and an organic phase rich in said C.sub.5+ hydrocarbons.