Four 12 month old crossbred Sindhi heifers (Red Sindhi × local Yellow cattle) with an average body weight (BW) of 79 (SD=9) kg were used to investigate the effect of fresh water hyacinth (WH) on intake and in vivo digestibility. The basal diet consisted of a molasses-urea cake (MUC) and rice straw. The animals were randomly allocated to four treatments in a 4×4 Latin square. The treatments were WH at 0 (WH0), 15 (WH15), 30 (WH30), and 45% (WH45) of an expected total dietary intake of 3% of body weight (BW). Molasses-urea cake was supplemented at a level of 3 g fresh matter per kg BW per day. When measuring intake, rice straw levels were adjusted daily to ensure an excess level of 10%. In the digestibility experiment, amount of rice straw was fed to ensure no refusals. Voluntary intake and digestibility were measured consecutively during the experimental periods which each lasted 28 days. Intake of neutral detergent fibre was lowest at the highest WH level but this was reversed for crude protein (CP). Total dry matter intake in percent of BW was 3.2, 2.9, 2.6 and 2.6 for WH0, WH15, WH30 and WH15, respectively and did not differ among treatments. Increasing level of WH had only an effect on CP digestibility which increased by 14 (WH15), 26 (WH30) and 24% (WH45) in comparison with treatment WH0. It is concluded that increasing level of WH in cattle diets considerably improved CP intake and digestibility but from problems experienced with WH45 in terms of bloat and reduced rice straw intake, an inclusion level not exceeding 30% is recommended for growing cattle. Cattle would also require long periods of adaptation to fresh WH to achieve reasonable intakes.