Hysteresis behaviour of the current–voltage characteristics collected on spin coated synthetic eumelanin layer embedded in the Au/eumelanin/ITO/glass structure is shown. The effect has been observed under dark both in air and vacuum environment and its magnitude has been found related to the eumelanin hydration state. Moreover, in vacuum and under white light illumination, enhancement of the hysteresis loop area respect to those collected under dark has been observed. Space charge storage and charge trapping/detrapping as possible mechanisms responsible of the observed current–voltage behaviour are discussed. Preliminary experimental results have evidenced the possible integration of eumelanin layers in electro-optical charge storage based memory devices.