The performance of a sieve plate electrochemical. reactor for the production of ethene oxide by the indirect electrochemical oxidation of ethene is reported. The oxidant is anodically generated bromine solution. The sieve plate reactor consists of a stack of bipolar electrodes situated above a sieve plate gas distributor. Two bipolar electrode materials are used graphite and IrO2 coated Ebonex(R). The influence of different sieve plate designs on performance is described. Control of electrolyte pH is shown to be an important requirement for efficient reactor operation.