[1] Satellite measurements from the Aura MLS instrument show a layer of OH near 82 km in the night. This layer confirms earlier measurements by ground-based LIDAR. The MLS and LIDAR observations measure OH in the lowest vibrational state and are distinct, but related chemically, from vibrationally-excited emission from the OH Meinel bands in the near infrared. The Caltech 1-D model has been extended to include vibrational dependence of OH reactions and shows good agreement with MLS OH data and with observations of the Meinel bands. The model shows a chemical lifetime of HOx that increases from less than a day at 80 km to over a month at 87 km. Above this altitude transport processes become an important part of HOx chemistry. The model predicts that ground state OH represents 99% of the total OH up to 84 km. Citation: Pickett, H. M., W. G. Read, K. K. Lee, and Y. L. Yung (2006), Observation of night OH in the mesosphere, Geophys. Res. Lett., 33, L19808, doi:10.1029/2006GL026910.