Abstract In a 24 hr period during 23–25 December 1975, I documented a minimum of 282 dead individuals of Oceanic Puffer Lagocephalus lagocephalus that had washed ashore on the remote South Atlantic island of Trindade, 1200 km east of the coast of Brazil. All of the more than 50 individuals for which I determined the sex had been reproductively active males. The locality is much farther south than the species has been previously recorded in the western Atlantic. I present evidence from ephemeral sources that report similar die-offs of Lagocephalus lagocephalus in the Hawaiian Islands and Fanning Atoll in the Pacific, and the Gulf of Guinea and Gabon in the eastern Atlantic for which, unfortunately, no scientific details, such as the sex of the individuals or other information that could explain cause of death, appears to have been published. The Trindade observation suggests that mass mortalities of this puffer may be associated with reproductive swarms.