The compression characteristics of thermoformable glass mat reinforcements with polyester binders have been studied as functions of temperature and platen closure rate. The mats were found to be more compliant and more compressible with increasing platen closure rate. At low closure rates, increasing the platen temperature has less of an effect on compressibility than at higher rates. Increasing the temperature also causes the mat to become more compliant. The compaction curves for the mats are described well with a logarithmic relation. This information is of interest to composite consolidation processes.