This article describes key findings from contemporary research on screening for early primary grade students in the area of mathematics. Existing studies were used to illustrate the constructs most worth measuring and the diverse strategies that researchers used to study potential measures. The authors discussed the strengths and weaknesses of assessing a few key proficiencies (as is often done in early reading) versus a more full-scale battery, and described the importance of going beyond merely reporting predictive validity correlation coefficients to examining the classification accuracy, specificity, and sensitivity of screening measures. [This article was published in "Exceptional Children," (EJ970689).]