The paper presents a new index which is an innovative tool for the analysis of the soil aggregates stability. The soil aggregates stability index (ASI) is based on a linear function value of the transition matrix elements with coefficients being properly chosen weights. Each element of the transition matrix is a relative frequency (empirical probability) of aggregates transition from one class of values to another or staying in the same class. The proposed weights give an ASI scale of values from 1 to 32 and are constructed this way that a higher ASI value corresponds with a higher aggregates stability. The usefulness of the proposed index is presented by way of an example of three soils (Haplic Phaeozem, Mollic Gleysol and Orthic Rendzina) for which aggregate water stabi!ity was determined by different methods.