The association between hyporexia/anorexia, reduced food intake and disease-related malnutrition at hospital admission is well established. However, information on fluid intake according to nutritional risk has never been provided. Thus, we assessed the attitude and adequacy of fluid intake among case-mix hospitalised patients according to nutritional risk. A sample of 559 non-critically ill patients randomly taken from medical and surgical wards was evaluated. Nutritional risk was diagnosed by the Nutritional Risk Screening 2002. Usual fluid consumption the week before admission was assessed and categorised as < 5 and ≥ 5 cups/d (1 cup = 240 ml), with the acceptable intake being ≥ 5 cups/d. Prevalence of nutritional risk was 57·2 %, and 46·2 % of the patients reported a fluid intake < 5 cups/d. Multiple-adjusted logistic regression revealed that age ≥ 65 years (OR: 1·88 (95 % CI: 1·03, 3·43); P < 0·04), energy intake (for every 25 % increase in food intake compared with estimated requirements, OR: 0·37 (95 % CI: 0·25, 0·55); P < 0·001) and the number of drugs taken (every three-drug increase, OR: 0·63 (95 % CI: 0·44, 0·90); P < 0·02) were independently associated with inadequate fluid intake ( < 5 cups/d). A significant independent association was also found with nutritional risk (OR: 0·64 (95 % CI: 0·43, 0·95); P < 0·03). Nutritional risk appears to be positively associated with greater fluid intake in non-acute hospitalised patients, but both the reasons and the consequences of this relationship, as well as the impact on clinical practice, need to be explored. However, water replacement by oral nutritional support should take advantage of the patients' attitude to assuming a greater fluid intake, limiting at the same time fluid overload during the refeeding phase.