Even though Enterprise Resource Planning (EW) systems are increasingly implemented in today s business environment, results of ERP investments remain debatable. This study would like to investigate the financial impacts of ERP systems for the manufacturing sector in Taiwan. Findings demonstrate that most of performance indexes how no significant differences after ERP installation. Only two indexes such as Inventory Turnover and Average Number Days Inventory in Stock show significant improvement after 2 or 3 year ERP implementation. Other indexes such as Return on Equity and Return on Assets even have worse performance than before. This outcome implies that ERP systems have not shown significant benefits with respect to financial performance under our short-term observations. It may take longer period to see real financial advantages like the ERP vendors claimed.