Flexible large sheets of dimethylsiloxane-based inorganic/organic hybrids with sizes of similar to200 mm X 290 mm and similar to1.5 mm thickness have been fabricated from poly(dimethylsiloxane) (PDMS) and metal alkoxides of Zr and Ta. The hybrid sheets were characterized by XPS, EXAFS, FT-IR, HRTEM, and SAXS. The inorganic components derived from metal alkoxides in the dimethylsiloxane-based hybrid sheets were found to be present as oxide-like clusters with sizes of 2-3 unit or below, which were chemically attached to PDMS via M-O-Si bonds. The hybrid sheets showed high elongation, strength, and thermal stability. A high elongation of about 100% was observed in the hybrid sheets fabricated in Zr(OBUn)(4)/ PDMS = 2 at 180degreesC and a high tensile strength of about 3.0 MPa was observed in those fabricated in Zr(OBun)(4)/PDMS = 4 at 180degreesC. The flexibility of the hybrid sheets was kept at least to 200degreesC for 100 h in N-2. These features are thought to come from the inorganic components derived from metal alkoxides, which are close to the molecular-level size and behave as a strong cross-linking agent of PDMS chains.