A hybrid silkworm (Nd × watako) was reared for sericin-rich cocoon development. The degumming loss of the cocoon was as high as 91%. The sericin protein, which is extractable merely using boiling water, was hydrolyzed slightly, but the molecular weight remained high at around 250 kDa. The extracted sericin was fabricated to sheets and an electro-spun fiber mat.