seven rumen and duodenal cannulated lambs were used to evaluate the intake and the total and the partial apparent digestibilities of dry matter (dm), organic matter (om), crude protein (cp), ether extract (ee), neutral detergent fiber (ndf), acid detergent fiber (adf), cellulose (cel) and hemicellulose (hcel) of the stylosanthes guianensis hay. the diet was composed by the hay of s. guianensis plus mineral salt. the hay was offered ad libitum with the refusals estimated for being 20%. chromium oxide was used as an external marker, to estimate fecal production and digesta flow to the duodenum. the intake of dm and om of s. guianensis were 67.71 and 64.70 g/kg0.75, respectively. the total apparent digestibilities of dm, om, cp, ndf and adf were 49.2, 51.3, 61.2, 42.0 and 42.7%, respectively. ruminal apparent digestibilities of dm, om, ndf and adf were 75.8, 84.7, 89.64 and 90.6%, respectively, as a function of total apparent digestibilities. the ruminal digestibility of cp was 21.3%. the use of s. guianensis hay, harvested at advanced stage of maturity may be indicated for sheep, because its dm intake and digestibility allowed energy supply for their maintenance requirements.