This MSc thesis work is entitled "Characterization of Black Cotton soil from Index Properties inrnSebetta area". The study area located at 32km, Southwest of Addis Ababa in the Oromiarnregional state; covering an area of 126 km2.rnThe main objective of the study is to characterize the black cotton soil of the area from indexrnproperties. The index properties define certain physical properties used basically forrnclassification but also for correlation with engineering properties.rnThe methodologies employed to achieve the objective are literature review pertaining to thernarea, filed data collection on soil and rocks, laboratory testing of soil samples and data analysisrnand interpretation.rnThe study revealed that the geology of the area is represented by rocks of Tertiary age (65my)rnnamely; basalt, andesite, and ignimbrite, and Quaternary soil units. Four engineering geologicalrnrock units and three soil units were mapped.rnDisturbed and undisturbed soil samples were analysed for index tests, namely, particle sizerndistribution, Atterberg limits, free swell, and shrinkage limits, in the Central Laboratory ofrnGeological survey according to BS 1377: part 2: 1990 standard.rnLaboratory test results from the present and previous studies have shown that fines are over 90rn%. Liquid limit (LL) and plastic limit (PL) values are ranging from 50-110 %, 24-50 %rnrespectively. The free swell varies from 118-140 %, while the shrinkage limit test values rangernfrom 15-20 % respectively.rnThe main index properties used for identification and classification of black cotton soil are clayrnfraction (minus 2 micron), Atterberg limits, free swell, and shrinkage limits. Accordingly, thernblack cotton soil is potentially active and requires countermeasures