Background and aims: Knowledge of a person's weight is important for identifying malnutrition; occupational safety reasons; medication dosing and evaluating effectiveness of medical nutrition therapy. However, weighing of patients in hospitals is known to be problematic and suboptimal. Methods: Five annual cross-sectional audits of patients admitted to nine hospitals were conducted to determine the frequency that patients were weighed (i) on admission and (ii) during admission. Characteristics such as age, length of stay, the presence of cognitive impairment, culturally and linguistically diverse (CALD) background, mobility status and single room isolation were also recorded. Results: The frequency of weighing patients on admission was only 20.3%. Approximately 62.4% of patients had been weighed at least once during their admission. Individuals who were admitted to rehabilitation wards or those with independent mobility had significantly higher odds of being weighed during the admission, in addition to those with a longer length of stay (Odds Ratios 5.98 (95% CI: 2.51–10.3); 2.34 (95% CI: 1.60–3.4); and 1.05 (95% CI: 1.03–1.07) respectively, all p < 0.001). Differences between ward types were also evident with rehabilitation, paediatric, renal and mental health wards exhibiting a higher incidence of weighing patients during their admission. Conclusions: The practice of weighing patients in this health district was suboptimal and places patients at high risk of a deterioration in their clinical condition. Strategies to ensure all patients are weighed including those who have a short hospital stay and those with poor mobility is required.