The work aimed to determine the apparent and true ileal digestibility of the amino acids of tropical tree foliage (Trichanthera gigantea) or aquatic plant (Azolla filucoides) in pigs. The incorporation of 100 or 200 g/kg of either tree foliage or aquatic plant in the pig diet significantly reduced both ileal and fecal digestibilities of the dietary nitrogen and amino acids of the diets (P< 0.05). The results are discussed according to the pig digestive physiology and the forage properties.