The latest comprehensive classification of Avena species was established by Malzew in 1929. It has been used by oat workers until today, in spite of the fact that for decades it became gradually outdated partly because new data became available and partly because new species were discovered. This necessitated a new attempt to classify the oats. The present study uses new characters and various numerical taxonomic techniques such as Gower's coefficient of resemblance and eight sequential, agglomerative, hierarchical clustering strategies. Thus 80 different classifications were formed, of which 21 were chosen as admissible. The best classification among the 21 is that which contains maximum information in the information-theoretic sense, i.e., using Eastabrook's model for character analysis. The relationships between the various classifications and the best one are extrapolated through principal coordinate analysis using the information-theoretic correlations between pairs of classifications as measure of distance.As a result, seven groupings were recognized, and canonical analyses were performed on these. Subsequently the canonical loadings were used here as unorthodox diagnoses for the seven groupings, which were then designated as taxa at the sectional category. A formal treatment of these newly established sections is provided in compliance with the rules of nomenclature.Finally, interrelationships between species are also studied using overlapping clusters based on the method of maximal complete subgraphs of Jardine and Sibson.