One of the most important processing operations in the fabrication of honeycomb composite structures is the forming of the honeycomb core. High performance honeycomb structures must be precisely formed, or contoured, in order to meet the strict dimensional specifications required by the end user of the core. However, in the composites industry today, there is no basic understanding of the high temperature behavior of honeycomb materials, which is fundamental to understanding the commercial processing of honeycomb composite structures. Zn this study, the thermal and mechanical responses of Nomex(R)-based honeycomb core were investigated and characterized through thermal analysis. In the ribbon direction of the core, specific post-cure temperatures were identified where the honeycomb core displayed a maximum degree of creep. In the expanded direction of the honeycomb, the core displayed no maximum-creep temperature. This behavior was attributed to the degradation of the node adhesive. A honeycomb creep time constant (tau(c)) was also defined and evaluated as a function of the honeycomb post-cure temperature. From this analysis, the softening of the dip resin was determined to play a larger role in creeping and deforming the core than the mechanical properties of the Nomex substrate.