This work examines the fatigue behavior of additive cold spray (CS) repairs of AA7075 and AA2024 fastener holes. Structural ring repairs around fastener holes were made by machining blend-outs ranging from 1/8 to 1/2 the thickness of the plate, then refilling the section of removed material with CS deposition. The repairs were then tested in a lap shear geometry with the repair on both the free (outside), and the mating (inside) surfaces, as well as in remote uniaxial tension. CS repairs for the inside lap shear AA7075 repair configuration and the outside lap shear AA2024 repair configuration were found to have significantly increased fatigue lives even exceeding the number of cycles to failure of the undamaged, unrepaired control plates. Further, none of the CS repairs caused any detrimental impact on fatigue life, and microhardness results indicate that no thermal damage to the substrate occurred. Some interface cracking was seen in the CS repairs, however no separation of the repair from the substrate was observed. I. INTRODUCTION Cold spray (CS) is a solid-state material deposition process that uses the kinetic, rather than thermal, energy of the impacting particles to bond with the substrate. In the CS process, high pressure gas is expanded through a converging diverging (de Laval) nozzle causing it to accelerate, speeding up the suspended powder with it. The exit velocity depends on the gas type, input pressure, temperature, and nozzle geometry, and varies from 200-1500 m/s [1]. Various gases can be used in CS, including compressed air, N 2 , and He, the latter of which, because of its lower molecular mass allows for higher gas and thus particle velocities. The impact velocity is one of the primary parameters that determines the quality of the deposit. Increasing the particle velocity generally leads to enhanced particle deformation, bonding, and compaction, resulting in increased density, and electrical, thermal, and mechanical properties of the deposited material [1, 2].