The transformation of natural ecosystems into agricultural environments modifies the soil structure and it may result in its compaction. Therefore, the objective of this work was to determine the optimum moisture for soil compaction (wot) and maximum soil compaction density (Dsmax) in different soil classes in western Bahia State. The samples were collected in five sites covering different soil classes: Orthic Quartzarenic Neosol (RQ), Orthic Ebanic Vertisol (VEo), Haplic Cambisol (CX) and two Red-Yellow Latosol, one already cropped (LVA) and another with native forest (LVA1).  Wot and Dsmax were determined according to ABNT NBR 7182 (1986) standards. Data were submitted to a regression analysis and also to the analysis of the principal components (PCA).  Wot presented a decreasing order: VEo> LVA> LVA1> CX> RQo, ranging between 8.20 and 15.00% and Dsmax showed the following order RQo> LVA> LVA1> CX> VE, ranging between 1.34 and 1,92 Mg.m-3. The wot was directly proportional to the clay content and the organic carbon and inversely proportional to the soil sand content. For Dsmax, the influence of the clay was inversely proportional whereas in wot, this variable promoted the growth.