An investigation was conducted into the effects of sodium hydroxide treated maize straw on the water intake of milch goats when fed alone or in a complete mixed diet. Dry matter intake was more closely related to water intake than to live mass. When untreated and sodium hydroxide treated maize straw fed ad lib. were compared it was found that sodium hydroxide treatment increased water intake by more than 50 percent. In the case of complete mixed diets water intake was increased when the diet contained 60 percent sodium hydroxide treated maize straw (5% NaOH treatment) or when the sodium intake was 18 mg per g of feed. The surplus sodium was excreted via a higher urine concentration of sodium and an increased urine volume.