Abstract: Among decision tree classifiers, Bayesian classifiers, k-nearest-neighbor classifiers, case-based reasoning, genetic algorithms, rough sets, and fuzzy logic which are some common classification methods in data mining, decision tree classifier is the most commonly used because it is easier to understand and implement compared to other classification methods. In this study, performance evaluation of two decision tree algorithm named ID3 and C4.5is done in order to discover which one is superior on the basis of accuracy with the help of a software tool using publicly available datasets.