AimsTo explore the prevalence of vitamin C deficiency, ‘undetectable’ vitamin C status, and scurvy features, in adult hospitalised patients with protein‐energy malnutrition diagnosed using validated malnutrition screening and assessment tools commonly used in clinical practice.MethodsThis study included adult inpatients from four acute hospitals within a single Australian tertiary health service, over a 3.5‐year period. A medical file review activity retrospectively determined malnutrition risk and diagnosis, via Malnutrition Screening Tool, Malnutrition Universal Screening Tool, Subjective Global Assessment and Global Leadership Initiative on Malnutrition criteria. Prevalence of vitamin C deficiency and scurvy features was examined in adult patients with plasma vitamin C levels <11.4 μmol/L and <5 μmol/L (‘undetectable’), respectively.ResultsIn the final cohort (n = 364), prevalence of vitamin C deficiency was 30.2%. Malnutrition was present in 76.1% and 79.8% of patients via Subjective Global Assessment (n = 310) and Global Leadership Initiative on Malnutrition criteria (n = 342) respectively. Patients with high nutrition risk and those diagnosed with severe malnutrition had the highest prevalence of vitamin C deficiency, reported as 32.8% for malnutrition detected via Malnutrition Screening Tool (n = 244), 32.9% via Malnutrition Universal Screening Tool (n = 222), 35.8% via Subjective Global Assessment (n = 106), and 34.2% via Global Leadership Initiative on Malnutrition (n = 152). Scurvy features were associated with severe malnutrition in patients with ‘undetectable’ vitamin C status.ConclusionsSeverely malnourished adult hospital patients have a high prevalence of vitamin C deficiency, and scurvy features in those with ‘undetectable’ vitamin C status. Leveraging existing malnutrition screening and assessment practices may support early identification of patients with vitamin C deficiency during hospitalisation.