Abstract: The motility of Shewanella Oneidensis (S. oneidensis), a facultative anaerobic capable of electron donation to extracellular electron acceptors such as electrodes or metal oxides, is mediated in both aerobic and anaerobic environments by the self-secreted electron shuttle riboflavin. Riboflavin acts as an electron shuttle in the reduction of electron acceptors and is a putative chemoattractant. Studies in a gradient-generating microfluidic device show that increasing concentrations of supplemented riboflavin increases migration speed of cells. In addition, S. oneidensis motility increases with oxygen depletion. Experiments on riboflavin chemotaxis are not conclusive, and require further studies. Quantifying riboflavin-mediated motility would allow for a better understanding and optimization of S. oneidensis electron donation within a bioelectrochemical system (BES).