INTRODUCTION AND AIMS: Malnutrition is frequent in patients with idiopathic pulmonary fibrosis (IPF). We examined the relationship between malnutrition at diagnosis and all-cause hospitalization, survival, and acute exacerbation in newly diagnosed IPF patients. METHODS: In this prospective cohort study, the nutritional status of 153 consecutive newly-diagnosed IPF outpatients was evaluated by measuring body mass index (BMI), fat-free mass index (FFMI) with bioelectrical impedance analysis, and food intake with the Self Evaluation of Food Intake (SEFI)®. Diagnosis was taken as the baseline date and malnutrition was defined as an FFMI below 17 (men) or 15 kg/m(2) (women). To determine the factors associated with all-cause hospitalization and mortality, univariate Cox regression analyses were performed and variables with P < 0.2 were included in a stepwise multivariable analysis. RESULTS: A quarter (26%; 40/153) of the patients were suffering from malnutrition at baseline, which was more frequent (62%) in patients whose BMI was <25 kg/m(2). Patients whose baseline FFMI was low were more likely to be hospitalized (Hazard Ratio (HR) = 1.98 [95% confidence interval, 1.15; 3.41], P = 0.0139) and/or die (HR = 1.79 [1.11; 2.89], P = 0.0165), but their acute exacerbation rate was similar to that of patients with normal FFMIs. Decreased food intake (SEFI®<7) at baseline was associated with all-cause hospitalization (P = 0.003) and mortality (P < 0.0001) during follow-up. Baseline higher gender-age-physiology (GAP) scores (HR = 1.24 [1.01; 1.52], P = 0.0434; HR = 1.71 [1.37; 2.14], P < 0.0001, respectively), lower BMI (HR = 0.89 [0.83; 0.96], P = 0.003; HR = 0.89 [0.82; 0.96], P = 0.003), and decreased food intake (SEFI® score) (HR = 0.81 [0.71; 0.93], P = 0.003; HR = 0.72 [0.64; 0.81], P < 0.0001), but not FFMI, were independently associated with all-cause hospitalization and mortality rates during follow-up. CONCLUSIONS: Malnutrition and decreased food intake at IPF diagnosis are associated with all-cause hospitalization and mortality. Future studies will determine whether dedicated interventions to improve food intake and nutritional status could improve outcomes for IPF patients.