[en] This letter reports on electric field induced pattern formation on a spin-coated PMMA layer. The PMMA layer is coated onto p-type silicon substrate using a spin coater at 3000 rpm. A perpendicular electric field is produced by applying a potential difference between the PMMA film and a parallel plate ITO conductor with water trapped between them. Different patterns are formed on PMMA and ITO layers depending upon the strength of electric field and time duration. The formed patterns are studied by scanning electron microscopy and atomic force microscopy. Mechanism of pattern formation and examination of formed pattern are discussed in this report. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)