The chemical ordering of FePt requires an annealing temperature >500 °C. At these temperatures, grain growth attributed to thermal annealing lowers the areal density in computer hard drives. Multiple paths have been proposed to lower the ordering temperature in order to decrease the grain growth. Ternary additions show promise as a way to lower the ordering temperature and decrease the grain growth. Though multiple studies have been conducted on the incorporation of Cu into FePt, these studies have produced contradictory results on the ordering temperature. Currently, there is no literature on the in situ growth stresses during deposition of FePtCu as a function of ordering temperature.InsituFe_44.5 Pt_51 Cu_4.5 and Fe_50 Pt_50 (for comparison) thin films were produced in order to determine how stress and ordering are affected by the incorporation of Cu. The incorporation of Cu at the amounts studied did not change the stress behavior of FePt when compared to Fe_50 Pt_50 . The addition of Cu raised the ordering temperature and had little to no effect on the grain size as compared to the Fe_50 Pt_50 . This retardation of ordering has been explained by the placement of Cu at lattice sites which minimize the bond distance to Pt and maximize the bond distance to Fe.