Petrels are among the most threatened group of birds. On top of facing predation by introduced mammals and incidental bycatch, these seabirds have to deal with an emerging threat, light pollution. Fledglings are disoriented and attracted to artificial lights in their maiden night flights from their nests to the sea. Once grounded, they are exposed to multiple threats leading to high mortality. We report on numbers of three petrel species (Balearic shearwater, Scopoli's shearwater, and European storm-petrel) rescued on the Balearic Islands. The proportion of grounded fledglings was lower than 1 % of the fledglings annually produced by the population. Although impact seems to be low for all species, urban development and, consequently, the increase in light pollution in the proximity of the colonies should be taken into account to reduce as much as possible this emerging source of mortality. informacion[at]ebd.csic.es  Rodríguez et al (2015) Artificial lights and seabirds: is light pollution a threat for the threatened Balearic petrels? J Ornithol DOI 10.1007/s10336-015-1232-3