Cool Stars 14 - Submitted Abstract # 372 This version created on 05 October 2006 Mid-IR observations of Upper Scorpius ultracool dwarfs H. Bouy N. Huelamo E. L. Martin D. Barrado M. Sterzik E. Pantin We present results of mid-IR observations of a sample of 11 ultracool dwarfs (SpT>M5.5) of the Upper Scorpius OB association. Seven of our targets are detected in the mid-IR. We derive a disk frequency of 50%, much larger than the accretor frequency (16%). Four of the targets were multiple system candidates. ----------------------------------