Palms (Arecaceae) are a dominant element within the neotropical plant community and because they substantially contribute to the overall and year-round fruit availability they are considered a key resource for frugivores, particularly for peccaries. Similarly, peccaries (Tayassuidae) are a dominant element within the neotropical mammal community. Their evolution of a strong mastication apparatus, unique interlocking canines, patterns of movement, and foraging ecology are viewed as adaptations to exploit hard seeds, particulary palm seeds. But how strong are the interactions between peccaries and palms, and what are the ecological ramifications? This review synthesizes over 76 papers, published between 1917 and 2004, which revealed that peccaries consumed fruits from 46 palm species, 73% of whose seeds were destroyed after ingestion. Furthermore, peccaries disperse palm seeds; eat flowers, seedlings, and roots; and trample seedlings. Thus, peccaries affect the spatiotemporal distribution and demography of palms. Local extinction of peccaries resulted in dramatic changes in the forest ecology. New conservation strategies are required to protect peccaries and prevent negative cascading effects.