In view of the low pasture productivity in the Central American humid tropics where cattle rearing is a major land-use activity, it is important to examine the potential of alternate feed sources for ruminant feeding. Erythrina berteroana Uban, locally known as poro, and green banana (Musa AAA) fruits have been identified as two such potential sources. The effects of feeding poro as a grazing supplement and diet supplementation with green banana fruits on cattle productivity were evaluated in a long-term trial in Costa Rica. Daily liveweight (LW)