There is a belief that timely and precise data are important to decisions and the better decisions are related to better firm performance. However, empirical research investigating the effect of data quality on firm financial performance is still scarce up to recently. Current study empirically explores such an effect of data quality on firm accounting performance in the Korean manufacturing industry during 2008~2010 with secondary data. The results show that better data quality does not impact on sales and operating profit, but positively and significantly impacts on EVA(Economic Value Added). Raising the level of data quality management maturity by one level can increase EVA by about 34% in manufacturing firms.