Document categorization or document classification is the process of assigning a document tornone or more classes or categories. Many researches are conducted in the area of Amharicrndocument categorization. The main focus of those studies is to examine different documentrncategorization techniques and measuring their performance however itemsets method is not sornfar examined. This study focused to extend Apriori algorithm which is traditionally used forrnthe purpose of knowledge mining in the form of association rules.rnThe research focused on the basic principles of applying itemsets method to categorizernAmharic documents. In addition to that the implementation of all the required tools whichrnhelps to carry out automatic Amharic Document categorization using itemsets method isrndeveloped and the algorithm is examined. Experiment results show itemsets method is anrnefficient method to categorize Amharic documents. The effectiveness and accuracy of thernmethod to categorize Amharic documents is also evaluated and reported. Finally, factorsrnaffecting the performance of the proposed system and the importance of preprocessing trainingrndataset in finding useful information are discussed.