[en] Quasi-isotropic laminates ([0/90/ +- 45]/sub s/; [0/ +- 45/90]/sub s/) were fabricated from graphite/epoxy and quasi-statically loaded in tension at 76 K until fracture occurred. Fibers in 0⁰ plies carry the largest portion of the tensile load; the weaker 90⁰ and 45⁰ plies crack at loads much lower than fracture strength. The effect of ply crack on fracture of load-bearing 0⁰ plies was examined to understand how defects affect laminate strength. A generalized plane-strain finite-element model was used to predict stress gradients in the 0⁰ ply near the crack tip. Variations in residual stress caused by changes in temperature and absorbed moisture were included in the analysis. The experiments indicated that absorbed moisture significantly alters the fracture strength and fracture surface of a dehydrated [0/90 +- 45]/sub s/ laminate tested at 76 K. The 0⁰ plies of dehydrated laminates fractured along several 90⁰ ply cracks. When moisture saturated a [0/90/ +- 45]/sub s/] laminate, a single 90⁰ ply crack dominated the fracture of the 0⁰ ply and the laminate fracture strength decreased 8 percent. Analysis of residual stresses indicated a higher residual stress state existed near the 90⁰ ply crack when moisture was absorbed