Aim To date, few studies have focused on the nutritional status of elderly hospitalized patients with diabetes. Our aims were to explore the prevalence of malnutrition among elderly diabetes patients admitted to the hospital, and to explore the relationships between malnutrition and geriatric syndromes, diabetic complications, and clinical outcomes. Methods A prospective, observational study including diabetes patients aged ≥65 years was carried out in a central hospital in Western China. Nutritional status was assessed using the Mini Nutritional Assessment incorporated into a comprehensive geriatric assessment. Follow up was carried out for ≤2.8 years. Results Of 302 participants, the prevalence of malnutrition, risk of malnutrition, and normal nutrition was 18.5%, 33.1% and 48.3%, respectively. In multivariate analysis, incontinence (odds ratio [OR] 3.17, 95% confidence interval [CI] 1.08–9.36), diabetic microvascular complications (OR 2.22, 95% CI 1.06–4.61) and activities of daily living (ADL) dependence (OR 11.6, 95% CI 5.10–26.5) were independently associated with malnutrition. Malnourished patients had longer hospital stays (P = 0.003) and higher mortality rates (P < 0.001) than patients either at risk of malnutrition or with a normal nutritional status. Multivariate analysis also showed that malnutrition was independently associated with an increased risk of death (OR 2.86, 95% CI 1.30–6.28). Conclusions The present study showed a high prevalence of malnutrition among elderly diabetes patients hospitalized for geriatric care. Considering the negative impact of malnutrition on hospital stay and mortality, adequate nutritional care should be emphasized for each elderly patient with diabetes, regardless of body mass index. Geriatr Gerontol Int 2017; ••: ••–••.