Between 2009 and 2015 we monitored 27 Crowned Solitary Eagle reproductive territories which we recorded active and inactive nests and we evaluated the reproductive success of this endangered species in central Argentina. In all reproductive events, the laying size was a single egg (n = 57) and we confirmed that the Crowned Solitary Eagle tries to breed every year although only few pairs can do it successfully. Hatching success per pair/year was 0,71 ± 0,16 (range = 0,50-1, n = 57), while total reproductive success was 0,60 ± 0,13 (range = 0,50-0,83, n = 57) chicks per pair/year. We recorded a greater failure during the incubation stage (n = 18) than in the rearing stage (n = 6). Infertility of the egg (n = 9) and anthropic disturbances (n = 5) were the main suspected causes in the incubation. Storms (n = 3) and fires (n = 2) were the natural factors that determined failure in both stages. Predation of a chick and drowning were exclusive causes of failure during rearing (n = 2). The drowning of an adult had generated the desertion of the nest by the other adult with the consequent death of the chick by starvation. Environmental education activities, working together with local farmer to reduce disturbances in the vicinity of nest during breeding, maintenance of firebreaks and the use of effective mitigation measures such as wildlife rescue ramps in the Australian tanks could decrease considerably the reproductive failure contributing to the recovery of the species in the region.