We report the results of a study of the near infrared reflectance spectra of decaying forest foliage. During the decay process, a broad absorbance feature develops in the 1100–2000 nm region of the near infrared spectrum. The magnitude of this feature is directly related to the age of the material (or to degree of decomposition) and may be useful in determining degree of decay in field samples. More specifically, multiple linear regression equations derived from second-derivative near infrared reflectance spectra are presented that predict the concentrations of nitrogen, lignin, and cellulose in decaying foliage. We conclude that near infrared reflectance spectroscopy is a very viable and attractive method for the simultaneous determination of these components in decaying foliage.