We developed a new detection scheme for the identification of thin cirrus based on a combination of the 1.38 ¿m and 0.65 ¿m reflectance ratio and 8.6--11 ¿m brightness temperature difference. Results computed from a radiative transfer model as well as data obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra satellite were used to demonstrate the applicability of this method for regional mapping of thin cirrus. The mm-wave radar backscatter data, coincident and collocated with MODIS data, available from the DOE's Atmospheric Radiation Measurement (ARM) sites, was employed for validation of the present satellite detection results. In all cases selected, our new method was able to detect the majority of thin cirrus estimated to have optical thickness between 0.1 and 0.9. It also compared favorably to existing detection tests.