We report the fabrication and accurate measurement of propagation and bending losses in single-mode silicon waveguides with submicron dimensions fabricated on silicon-on-insulator wafers. Owing to the small sidewall surface roughness achieved by processing on a standard 200mm CMOS fabrication line, minimal propagation losses of 3.6±0.1dB/cm for the TE polarization were measured at the telecommunications wavelength of 1.5µm. Losses per 90° bend are measured to be 0.086±0.005dB for a bending radius of 1µm and as low as 0.013±0.005dB for a bend radius of 2µm. These record low numbers can be used as a benchmark for further development of silicon microphotonic components and circuits.