Decreased Transthyretin (TTR) can be observed in heart failure patients with malnutrition evaluated by the Mini Nutritional Assessment (MNA). This study investigated whether a combination of different nutritional assessment methods would be useful for assessing prognosis in patients with acute decompensated heart failure (ADHF).This prospective study included 52 patients with ADHF (mean age, 71.1 ± 14.7 years; men 55.8%) who were admitted to our hospital between June 2012 and August 2013. On admission, nutritional status was evaluated according to levels of TTR and the MNA. Of 52 patients, 28 (53.8%) had TTR < 15 mg/dL, 39 (75.0%) had malnutrition or were at risk of malnutrition (MNA score ≤ 23.5), and 21 (40.4%) were categorized into group L (MNA score ≤ 23.5 and TTR < 15 mg/dL). Readmission due to worsening heart failure occurred in 12 patients (23.1%), and there were 4 (7.7%) allcause deaths. The 1-year event-free survival rates in group L and the remaining patients (group O) were 27.7% and 85.6%, respectively (P = 0.001). Using Cox multivariate analysis, group L also had a poorer prognosis (hazard ratio 4.35, 95% confidence interval 1.26-17.74, P = 0.020).MNA revealed that 75% of patients with ADHF had malnutrition or were at risk of malnutrition. The combination of low MNA and low TTR on admission can predict the prognosis of patients with ADHF.