(1) Background: Malnutrition in hospitalized patients is prevalent worldwide, but the severity of the issue is often underestimated by practitioners. The purpose of this study is to investigate the prevalence of malnutrition and inadequate eating behaviour in a geriatric sample. (2) Methods: Two hospitals participated with six wards on nutritionDay in 2017, 2018 and 2019. Nutritional status, food intake, and nutritional interventions were analyzed for all patients ≥ 65 years (
n = 156), using the official nutritionDay questionnaires. Malnutrition risk is identified by Malnutrition Universal Screening Tool (MUST), malnutrition by the ESPEN criteria (European Society of Clinical Nutrition and Metabolism). (3) Results: According to MUST (
n = 136) 16.9% (
n = 23) were at medium risk of malnutrition, 33.8% (
n = 46) at high risk of malnutrition, 28.1% (
n = 38) were malnourished. Overall, 62.8% (
n = 98) showed an inadequate eating behaviour during hospital stay. Moreover, patients with inadequate nutrition had significantly worse self-reported health statuses (
p = 0.001; r = −0.276), were less able to walk on nutritionDay (
p = 0.002; r = −0.255), had eaten little in the week before admission to hospital (
p < 0.001; r = −0.313), and had an increased length of stay (
p = 0.036; r = −0.174). (4) Conclusion: To identify malnourished patients is a significant barrier for practitioners seeking to administer specific, tailored interventions. Malnutrition screening protocols must be improved, just as nutrition monitoring in general.
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