We report on the fabrication and characterization of hybrid-organic memory devices based on gold (Au) nanoparticles that utilize metal–insulator–semiconductor structure. Au nanoparticles were produced by sputtering and inertgas condensation inside an ultrahigh-vacuum compatible system. The nanoparticles were self-assembled on a silicon dioxide (SiO2)/silicon (Si) substrate, then coated with a poly(methyl methacrylate) (PMMA) insulating layer. Aluminum (Al) electrodes were deposited by thermal evaporation on the Si substrate and the PMMA layer to create a capacitor. The nanoparticles worked as charge storage elements, while the PMMA is the capacitor insulator. The capacitance–voltage (C–V) characteristics of the fabricated devices showed a clockwise hysteresis with a memory window of 3.4 V, indicative of electron injection from the top Al electrode through the PMMA layer into Au nanoparticles. Charge retention was measured at the stress voltage, demonstrating that the devices retain 94% of the charge stored after 3 h of continuous testing.