For the first time, a totally solid state electric double layer capacitor has been fabricated using an alkaline polymer electrolyte and an activated carbon powder as electrode material. The polymer electrolyte serves both as separator as well as electrode binder. The capacitor has a three-layer structure: electrode–electrolyte–electrode with a final thickness of ca. 1.5–2 mm, diameter of 1.8 cm (surface of 2.5 cm2) and a mass of ca. 300–500 mg. Cyclic voltammetry, galvanostatic cycling and impedance spectroscopy have been used for the determination of the electrochemical performance of prototype capacitors and a capacity of ca. 1.7–3.0 F for a 1 V voltage range has been measured.