The traditional method of determining dust lead loading (mass per unit area) on surfaces is to send dust wipe samples to a laboratory for analysis, and typically it takes one or more days to obtain results. Field-portable techniques taking 10 to 15 min for dust wipe lead analysis have been developed but need to be further evaluated. Dust wipe samples (n = 878) collected from a nationally representative sample of child care centers were tested by means of x-ray fluorescence (XRF) analysis with two XRF analyzer instrument models and subsequently analyzed for lead using flame atomic absorption spectrometry (FAAS). Samples were collected from floors and interior window sills and included blank and spiked quality control samples. Weighted linear regression was used to model the relationship between XRF and FAAS measurements. The correlations between FAAS and XRF measurements exceeded 0.80 (p