Abstract This study reports the digestibility of neutral sugars in immature leaves, immature stems, and mature stems of legumes and grasses. The basal 200 mm of immature and mature stems, and leaves from immature plants, of alfalfa ( Medicago sativa L.), birdsfoot trefoil ( Lotus corniculatus L.), smooth bromegrass ( Bromus inermis Leyss.), and orchardgrass ( Dactylis glomerata L.) were collected from a replicated field experiment. Ground plant tissue was incubated in buffered rumen fluid for 72 h. Neutral sugar digestibility most adversely affected by stem maturity was that of glucose and xylose. Digestibility of these sugars was much greater in leaves than in stems of both grasses and legumes. Xylose had the lowest digestibility value of the neutral sugars and this value was particularly low in legume stems. Up to three-quarters of xylose was digestible in leaves, about half was digestible in grass stems, and less than one-quarter was digestible in legume stems.