Captive propagation of Andean Condors (Vultur gryphus) was initiated at the Patuxent Wildlife Research Center in 1966 in anticipation of the need to apply resulting techniques to the captive breeding of the endangered California Condor (Gymnogyps californianus). This report summarizes the progress made on this Andean Condor breeding and research project, with emphasis on recent fostering/cross-fostering studies. These studies include: (a) fostering eggs/chicks between Andean Condors; (b) fostering of two chicks each to Andean Condor pairs; (c) cross-fostering of a Turkey Vulture (Cathartes aura) to Andean Condors; and (d) cross-fostering an Andean Condor chick to wild California Condors. Implications of these studies for the recovery of the California Condor will be discussed.