Due to increasing power densities and decreasing device footprints, thermal management has become an important design requirement in modern electronic devices. Loop heat pipes are phase change-based devices that can absorb and transport large heat fluxes via the latent heat of evaporation of a working fluid. However, these devices are bulky and difficult to miniaturize due to the constraining effect of undesired parasitic heat flow and other thermodynamic considerations of the two-phase flow loop. Here, we present experimental results demonstrating the operation of an ultra-thin microscale loop heat pipe that employs a planar evaporator wick designed to counter the negative effects of parasitic heat flow. Despite the extremely low wick thickness (< 0.5 mm), the device is able to successfully startup, with no apparent observation of a wick dry-out due to parasitic heat flow-induced disruptions of liquid supply to the evaporator. A latent heat flux of approximately 6.7 W/cm2 is absorbed per unit area of the evaporator during the device startup phase.