The availability of psychometrically sound and usable universal screeners is a key component to successful early identification within a response-to-intervention model. The purpose of this study was to compare the diagnostic accuracy of oral reading fluency (ORF) and an informal reading inventory for identifying students considered at risk for failing a district-wide assessment. Participants included 968 students in 2nd and 3rd grade in a rural elementary school district in Minnesota. Results showed significant correlations between ORF and informal reading inventory data and between each potential screener and the criterion measure at 2nd and 3rd grades. However, ORF demonstrated higher diagnostic accuracy for correctly identifying at-risk students and resulted in 80% correct classification compared to 54% for the reading inventory data. We discuss implications for practice and directions for future research.