Memory properties of a nanodot-type floating gate memory with Co-bio-nanodots (Co-BNDs) embedded in HfO2 were investigated. High density and uniform Co-BNDs were adsorbed on a HfO2 tunnel oxide using ferritin. The fabricated MOS capacitor exhibited a capacitance-voltage curve with large hysteresis. The memory window size was 30 times larger than that of the MOS capacitor with an SiO2 gate oxide. Not only a large memory window but also excellent charge retention and reliability characteristics were obtained for an MOS field-effect transistor. The high-performance nanodot-type floating gate memory was first fabricated at low temperature by utilizing supramolecular protein.