Öz
ERP (Enterprise Resource Planning) software are the advanced solutions which tailored for whole enterprise needs and target high efficiency in production & service issues. In this study, the benefits of ERP upgrading in enterprises and the required infrastructural issues prior to this upgrading are revealed by employing the clustering and association rules, which are among the descriptive data mining methods. In clustering study, the natural differences are revealed between the companies which have ERP system and which do not. When the results are examined. It is established that recent capacity usage ratios and owning some departments have high correlations with having ERP system. On the other hand, frequently observed patterns are extracted in companies with and without ERP by association rules analysis.