Soil formation processes can be characterized by soil pore properties. As soils develop more, the quantity of larger pores increases, consequently increasing the total porosity and changing pore size distribution. Since the larger pores are created by biological activities, spatial variability of the larger pores becomes higher during the soil formation processes. The objective of this study is to analyze the spatial variation of the pore size distribution to investigate soil formation. The sampling site is located within a 1-yr old Erva Mate (Ilex paraguariensis) plantation area at the Caguiri Farm of UFPR, Curitiba city - PR, Brasil. Soils are Inceptisols. Along the hillslope line and the line perpendicular to it, 54and 41 undisturbed soil samples of 100 cm3 volume, respectively, were taken from 0-5 cm depth which is a part of A-horizon. The membrane suction method was adopted to determine a retention curve for each sample. The suction values in the method were 0, 4, 7, 10, 20, 30, 40, 50 and 60 cmH2O.Considering theses values and the Laplace equation, the pore sizes were classified as, >750, 750-429, 429-300, 300-150, 150-100, 100-75, 75-60, 60-50 and 50 mm. The last range constitutes microporosity. Geostatistics analysis (autocorrelation and semivariance) did not show the tendency and frequency of spatial variability of pore distribution properties. The values of coefficient of variation decreased with the pore size. This indicates that larger pores have larger spatial variation. This implies that soil formation process occurs by the increase of the heterogeneity of parent materials with regard to pore size distribution.