The purpose of this study was to examine six early numeracy measures used to monitor the mathematics progress of kindergarten and first-grade students. Seventy-one kindergarten students and 75 first-grade students were administered the measures each week. Delayed-alternate form reliability was adequate for instructional decision making on some measures, and low reliability was reported for quantity discrimination, as well as for the next number and number facts measures. Concurrent criterion validity coefficients comparing the measures with student performance on the "Woodcock-Johnson Tests of Achievement--Third Edition" (WJ III) resulted in weaker coefficients as compared to previous studies that have compared similar measures with the WJ III. Hierarchical linear modeling was used at each grade level to ascertain the ability of the six measures to model weekly growth trajectories over 13 weeks. All measures produced growth rates that were significant across time, for both kindergarten and first grade, with linear growth observed for all measures. (Contains 4 tables.)