Decades of the New World (Latin: De orbe novo decades; Spanish: Décadas del nuevo mundo), by Peter Martyr d'Anghiera, is a collection of eight narrative tracts recounting early Spanish exploration, conquest and colonization of the New World, exploration of the Pacific, and related miscellany.

[1] Eden's translations were reprinted with supplementary materials in 1577 by Richard Willes under the new title, The historie of travayle into the West and east Indies.

The Decades describe the early contacts of Europeans and Native Americans derived from narratives of the voyages of Christopher Columbus in the Caribbean, reports from Hernán Cortés's Mexican expedition, and other such resources.

They consisted of eight reports, two of which Martyr had previously sent as letters describing the voyages of Columbus, to Cardinal Ascanius Sforza in 1493 and 1494.

In 1501 Martyr, as requested by the Cardinal of Aragon, added eight chapters on the voyage of Columbus and the exploits of Martin Alonzo Pinzón.