This document summarizes a study on modeling carbon fiber reinforced polymer (CFRP) cruciform specimens under biaxial fatigue loading. It describes the development of a biaxial loading mechanism that subjects cruciform specimens to tension-tension or compression-compression loading at ratios of 1:1 to 1:4. Finite element models of cruciform specimens with different layer configurations were created in ANSYS and fatigue analyzed in nCode DesignLife. Results showed that modeling the CFRP as orthotropic rather than isotropic reduced the predicted fatigue life, with the orthotropic material exhibiting greater sensitivity to load duration. Increasing layer numbers from 6 to 10 also increased fatigue life.