The file “Newcomer et al. 2012 (Ecological Monographs) Organic C and Denitrification in Streams.xlsx” provides original data from the manuscript. The worksheets are named to correspond with the figures in the manuscript. “Figure 4” has field measurements of nitrate and DOC loads (g ha-1 day-1) and runoff (mm day-1). We measured discharge at Spring Branch and discharge was downloaded from USGS gaging stations at the other sites. “Figure 5” was created using discharge (cfs) downloaded from USGS gaging stations and dividing it by watershed area to get runoff (mm day-1). “Figure 6” has field measurements of mean C:N molar ratios for leaves, periphyton, grass, sediment, and stream particulate organic matter (POM). “Figure 7” has field measurements of 15N and 13C stable isotope signatures for leaves, periphyton, grass, sediment, and stream POM. “Figure 8” has laboratory measurements of denitrification potentials associated with glucose versus nitrate amendments. “Figure 9” has laboratory measurements of denitrification potentials associated with the use of leaves, periphyton, and grass as a carbon source