Decision tree is one of the most popular and efficient technique in data mining. This technique has been established and well-explored by many researchers. However, some decision tree algorithms may produce a large structure of tree size and it is difficult to understand. Furthermore, misclassification of data often occurs in learning process. Therefore, a decision tree algorithm that can produce a simple tree structure with high accuracy in term of classification rate is a need to work with huge volume of data. Pruning methods have been introduced to reduce the complexity of tree structure without decrease the accuracy of classification. One of pruning methods is the Reduced Error Pruning (REP). To better understand pruning methods, an experiment was conducted using Weka application to compare the performance in term of complexity of tree structure and accuracy of classification for J 48, REPTree, PART, JRip, and Ridor algorithms using seven standard datasets from UCI machine learning repository. In data modeling, J48 and REPTree generate tree structure as an output while PART, Ridor and JRip generate rules. In additional J48, REPTree and PART using REP method for pruning while Ridor and JRip using improvement of REP method, namely IREP and RIPPER methods. The experiment result shown performance of J48 and REPTree are competitive in producing better result. Between J48 and REPTree, average differences performance of accuracy of classification is 7.1006% and 6.2857% for complexity of tree structure. For classification rules algorithms, Ridor is the best algorithms compare to PART and JRip due to highest percentage of accuracy of classification in five dataset from seven datasets. An algorithm that produces high accuracy with simple tree structure or simple rules can be awarded as the best algorithm in decision tree.