1-Introduction One of the essential requirements in the all stages of an EXPLORATION operation for deposits is the precise locating the EXPLORATION works or design of the EXPLORATION grid. In general, the arrangement of EXPLORATION works is called the EXPLORATION grid. The EXPLORATION grid has the variety of types that the type, shape and dimensions of the grid depend on the geological conditions and characteristics of the deposit (Ahmadi, 2005). Today, issues related to mineral EXPLORATION and design of EXPLORATION grids require the extensive use of all sciences, especially new sciences, fast, accurate and intelligent techniques (Smirnoff et al., 2008). In the present research, designing EXPLORATION grid has been carried out for Khomein-Robat Pb-Zn deposit as a worthwhile small-scale metallic deposit. The Robat Pb-Zn deposit is located in 32 km west of Khomein city, 10 km northwest of Ghourchi Bashi town and 2 km south of Robat-e-Paeen village. The studied region comprises three mineralized areas called Arregijeh, Takhte-Hossein and Baraftab where Takhte-Hossein and Baraftab are adjacent to each other. From structurally view point, the study area is located in the Sanandaj-Sirjan metamorphic zone and consists of Cretaceous carbonate-clastic cover over the old metamorphic complex. This region, in terms of mineralization, especially the presence of Pb-Zn minerals, is a part of the Malayer-Isfahan mineralization strip (Pichab kansar, 2009). According to the geological conditions of the deposit, the type and amount of available exploratory information (assay data of trenches, test pits, outcrops, semi-deep and deep boreholes) statistical and geostatistical methods have been used to design systematic EXPLORATION grid for Arregijeh region...