Several studies have found significant correlations between hot water extractable organic carbon and microbial biomass carbon, suggesting that the organic matter extracted by hot water is a useful index of labile carbon in the soil. However, little is known about the composition of hot water extractable carbon. We used elemental analysis and ¹³C nuclear magnetic resonance spectroscopy with cross polarization and magic angle spinning (¹³C CPMAS NMR) to examine the composition of hot water extractable organic matter (HWEOM) in a forest soil from New Hampshire. The samples were collected from Oi, Oe, and 1-cm increments within the Oa horizon of pedons under hardwood and conifer stands. HWEOM has less alkyl C and more O-alkyl C than the whole soil from which it is extracted. Extractable organic matter also has a lower C:N ratio than whole soil. Within the Oa horizon, the percentage of soil C extracted by hot water decreases with depth, corresponding to increasing alkyl C in the whole soils. The large changes in the amount and composition of HWEOM within the forest floor suggest a significant gradient in the amount and nature of labile C.