The effect of temperature, postcure, and fiber orientation on water absorption were examined for Kerimid(R) 723 bismaleimide resin. The effect of fiber orientation was also examined for Avimid(R) N and BASF X-5260. Water absorption in Kerimid(R) 723 was found to have an Arrhenius temperature dependence, depend on degree of postcure, and be independent of fiber orientation. BASF X-5260 water absorption was also found to be independent of fiber orientation. Avimid(R) N water absorption exhibited a strong dependence on fiber orientation.