Hornby's Storm Petrel Oceanodroma hornbyi is endemic to the Humboldt Current Region. Historically, little has been known about the location of the species' breeding sites or the size of its population. For these reasons, this species has been classified as ‘Data Deficient’ by IUCN, and it is difficult to know whether the species is threatened, and if so, what conservation actions may be necessary. As part of the project ‘Golondrinas del Desierto’ a search for the colonies of this species began in November 2013. It was known that the species breeds in the Atacama Desert, because some mummified individuals had been found there, and fledglings attracted by lights whilst on their way to the sea were found in nearby coastal cities. In this paper, we describe the first breeding site discovered for this species. This breeding location is 75 km from the shoreline, at 1100 meters above sea level, in the centre of the Atacama Desert, also known as the ‘absolute desert’. However, there is strong anthropogenic pressure on this desert due to the development of mines and solar energy projects. To protect these birds, it is important to estimate the breeding population size of the colony, search for new colonies and assess the threats to each of them, and to evaluate how many fledglings are drawn off course by lights into cities and industrial sites and how many die there.