Permanganate oxidizable carbon (POXC) is a newer method that can measure the labile soil C in a quick and inexpensive manner. POXC is typically positively correlated with particulate organic matter, microbial biomass C, and total soil organic matter. It is an efficient way of measuring differences in soils due to management and environmental factors. We measured POXC across three long-term experimental sites that represent a climate gradient across eastern Colorado. At each site, there were three no-till rotations used: wheat-corn (sorghum)-fallow (WCF), wheat-fallow (WF), and continuous cropping (CONT)-this includes both grain and forage crop rotations. All three treatments have been in place for the past 15 years. From each treatment, we collected soil at three depths: 0-2.5 cm, 2.5-5 cm, and 5-10 cm. We expected to see greater POXC content in the 0-2.5 cm depth compared to the 5-10 inch depth due to surface residue inputs and greater POXC in CONT than WF rotations. Soil POXC content was greater in the shallower soil depths (0-2.5cm and 2.5-5cm) than in the 5-10 cm depth at all sites. The CONT rotation had greater POXC than WCF at the two northern sites and there was no effect of rotation on POXC levels at the southern site with the highest potential evapotranspiration. These results show that climate and residue input influence the quantity and distribution of labile soil C within the soil profile.