Intraspecific predation (cannibalism) in brown bears (Ursus arctos) is a behavior rarely documented, and it remains poorly understood. In April 2010 we documented the probable killing and partial consumption of a subadult female bear by a subadult male bear; both bears had been captured during a telemetry study in northern Greece. Intraspecific killing was supported by a match between the inter-canine distance of the male, fatal wounds on the female, and the absence of other bear tracks at the trap site; consumption of the subadult female by the subadult male was witnessed directly by the trapping team. This is the first reported case of probable intraspecific killing and predation of a subadult female by a subadult male brown bear. Though intraspecific predation appears to be a rare phenomenon, trapping teams should always strive to reduce the time an animal is captured in a trap, such as by using trap alarms.