A novel biodegradable poly(ethylene succinate-co-diethylene glycol succinate) (PEDEGS)-based nanocomposite containing low loading (0.5 wt %) of octavinyl-polyhedral oligomeric silsesquioxanes (ovi-POSS) was prepared via a solution and casting method. Scanning electron microscopy images illustrated a nice dispersion of ovi-POSS in PEDEGS matrix. PEDEGS crystallized faster in the nanocomposite under isothermal melt crystallization conditions; moreover, the density of PEDEGS spherulites also increased, indicating ovi-POSS acted as a nucleating agent. Ovi-POSS crystallized separately in the PEDEGS matrix and did not alter the crystal structure of PEDEGS. The storage modulus of the nanocomposite decreased in the lower-temp eratiire range; moreover, the glass transition temperature of PEDEGS also decreased in the nanocomposite, indicating that ovi-POSS also acted as-a plasticizer and lubricant.