Analysis of atmospheric infrared absorption spectra and recent developments in infrared laser technology has lead to the development of a new and innovative laser hygrometer. The proposed new laser hygrometer offers an outstanding combination of accuracy, sensitivity, and response speed, coupled with high reliability and repeatability in harsh environments, non- cryogenic operation, compact size, low power consumption, and modest cost. The Phase I research objectives include design and construction of a proof-of-concept laser hygrometer, verification of its principal of operation and response function, plus research on a Phase II hygrometer design and Phase II work plan.