Three mature female cattle with an average body weight of 143 kg were surgically fitted with rumen cannula and used to determine the in situ nutrient degradabillty of some potential indigenous feed protein sources in fresh form. Gliricidia (Gliricidia sepium (Jacq.) Kunth ex Walp), binunga (Macaranga tanarius (L.) Muell. Arg.), Leucaena (Leucaena leucocephala (Lamk) de Wit.), anubing (Artocarpus ovatus Blanco), flemingia (Flemingia marcrophylla (Willd.) Merr.) and malaipil (Intia acuminate Merrill) were selected out of 22 fodder species screened, as the potential indigenous feed sources based on crude protein(CP) and condensed tannin (CT) content. Among the species, the degradability of dry matter (DM) and CP was highest in gliricidia and malaipil, but similar with that in flemingia. Extractable CT was negatively correlated with the digestibility of DM, CP and neutral detergent fiber (NDF) in all species in fresh form. Levels of tannin concentration and the physical preparation of the species influenced the relationship between tannin content and the rumen digestion kinetics of DM and CP. It Is concluded that the presence of high levels of tannin protected the plant proteins from degradation by the rumen microorganisms.