The research was carried out at the animal experimental station of the National Agricultural Research Institute of the French West Indies (Guadeloupe) in 1999. Effects on intake and digestion by sheep of addition of Gliricidia leaves to a diet of 35-day-old Digitaria decumbens (pangola) hay, have been studied. In a first trial (a 4×4 Latin Square design), four rams were fed four diets: hay (G0); hay plus 1300 g of Gliricidia (G0·25), hay plus 2600 g of Gliricidia (G0·50), hay plus 3900 g of Gliricidia (G0·75). Total dry matter intake (DM), hay and Gliricidia intake, total tract and rumen digestibility of DM and its components, microbial and total nitrogen flows were estimated. In a second trial (a 2×2 Latin Square design), the same animals received hay (G0) or Gliricidia (G1·00) ad libitum to estimate the rumen turnover of pangola and Gliricidia fibrous particle. Neutral detergent fibre and crude protein content of the Digitaria decumbens hay and Gliricidia were 746 and 51, 458 and 198 g/kg dry matter respectively. Total dry matter intake (DM) varied from 42·7 to 76 g DM/kg LW0·75 from G0 to G0·75. The rate of substitution of pangola by Gliricidia (decrease of pangola intake for one unit Gliricidia consumed) was 233 g/kg. The digestibility of cell-wall linearly decreased with increasing level of Gliricidia in the diet. No digestive interaction was registered in the mixed diets. The total nitrogen and microbial nitrogen duodenal flows increased with the level of Gliricidia in the diet. The rumen turnover of fibrous particles of Gliricidia was double that of pangola. The incorporation of Gliricidia in diets increases their nutritive value by higher intake and intestinal nitrogen duodenal flows, but no positive digestive interaction was observed between pangola hay and Gliricidia leaves.