NOVELTY - Preparing lower olefins from an oxygenate, comprises: (a) contacting the oxygenate with a molecular sieve-comprising catalyst; (b) separating ethylene and/or propylene and a fraction comprising 4C hydrocarbons including saturated and unsaturated 4C hydrocarbons from the olefinic product stream; (c) subjecting the fraction to extractive distillation; and (d) supplying the stream enriched in unsaturated 4C hydrocarbons and an alcohol comprising methanol and/or ethanol to an etherification reaction zone and reacting isobutene in stream enriched in unsaturated 4C hydrocarbons with alcohol.    USE - The process is useful for preparing lower olefins from an oxygenate (claimed) e.g. methanol and dimethylether, where lower olefins are ethylene and propylene.    DETAILED DESCRIPTION - Preparing lower olefins from an oxygenate, comprises: (a) contacting the oxygenate with a molecular sieve-comprising catalyst at a temperature of 350-1000 degrees C to obtain an olefinic product stream comprising ethylene, propylene and 4C hydrocarbons; (b) separating ethylene and/or propylene and a fraction comprising 4C hydrocarbons including saturated and unsaturated 4C hydrocarbons from the olefinic product stream; (c) subjecting the fraction comprising 4C hydrocarbons to extractive distillation to obtain a stream enriched in unsaturated 4C hydrocarbons comprising isobutene and n-butenes, and a stream enriched in saturated 4C hydrocarbons; (d) supplying the stream enriched in unsaturated 4C hydrocarbons obtained in step (c) and an alcohol comprising methanol and/or ethanol to an etherification reaction zone comprising an etherification catalyst and reacting the isobutene in the stream enriched in unsaturated 4C hydrocarbons with the alcohol in the etherification reaction zone to obtain an etherification product stream comprising alkyl tertiary butyl ether; (e) separating the etherification product stream into an alkyl tertiary butyl ether-enriched stream and an isobutene-depleted unsaturated 4C hydrocarbon stream; and (f) recycling the isobutene-depleted unsaturated 4C hydrocarbon stream and/or the alkyl tertiary-butyl ether to step (a).