Based on the fact that the insufficient supply of agricultural domestic animals with drinking water in tropical and subtropical regions is often the factor limiting their performance, the effect of different drinking water supply of sheep (ad libitum, 54% of ad libitum and 27% of ad libitum) on various parameters was studied. A water supply reduced to 54 and 27% resp. diminished dry matter intake to 84% and 45% resp. A water supply reduced to 54% improved the digestibility of organic matter, crude fibre, crude cellulose and N-free extractives, it was, however, not significant. A reduction to 27% of the ad libitum water supply improved the digestibility of all crude nutrients, significantly, however, only that of organic matter, crude fibre, crude cellulose and N-free extractives. In comparison with a supply of water reduced to 54%, a water supply reduced to 27% also resulted in an improvement of the digestibility of all crude nutrients. Both the reduction of the ad libitum water supply and the increasing time interval for the sampling of rumen fluid resulted in an increased concentration of volatile fatty acids in the rumen fluid, which was sampled 15 min, 1 hour and 2 hours after feeding.