A pyramid/nanowire binary structure is fabricated on the silicon surface via a NaOH anisotropic etching technique followed by a silver-catalyzed chemical etching process. The silicon surface shows a stable superhydrophobicity with high contact angle of 1628 and small sliding angle less than 28 after being modified with octadecyltrichlorosilane (ODTS). The binary roughness of pyramid/nanowire structure presents a stable composite interface of silicon-air-water and responsible for the superhydrophobicity of silicon surface. (C) 2009 Elsevier B. V. All rights reserved.