Crystallization is an attractive method for separation and purification of large biomolecules such as proteins due to inherent advantages related to product composition, stability, and process throughput. However, the lack of control over the nucleation and growth of protein crystals complicates design and operation. Electric fields have been used to improve control over the location and induction time of protein nucleation in small batches. To adopt electric-field-assisted protein crystallization as a separation and purification method, a novel device based on continuous flow is presented. The application of continuous flow allows for a large surface-to-volume ratio to be exploited for the electrode design and aligns with the current trend in the (bio)pharmaceutical industry toward continuous manufacturing. The device features millimeter-sized channels with coplanar electrodes to study the influence of nonuniform electric fields on protein crystallization in continuous flow. The results demonstrate that ...