Objective To analyze the criterion-related validity and user-friendliness of the Minimal Eating Observation and Nutrition Form – Version II (MEONF – II) and Malnutrition Universal Screening Tool (MUST) in relation to the Mini Nutritional Assessment (MNA). In addition, the effect of substituting body mass index (BMI) with calf circumference (CC) was explored for the MEONF-II. Methods The study included 100 patients who were assessed for nutritional status with the MNA (full version), considered here to be the gold standard, and screened with the MUST and the MEONF-II. The MEONF-II includes assessments of involuntary weight loss, BMI (or calf circumference), eating difficulties, and presence of clinical signs of undernutrition. Results The MEONF-II sensitivity (0.73) and specificity (0.88) were acceptable. Sensitivity and specificity for the MUST were 0.57 and 0.93, respectively. Replacing the BMI with CC in the MEONF-II gave similar results (sensitivity 0.68, specificity 0.90). Assessors considered MEONF-II instructions and items to be relevant, easy to understand and complete (100%), and the questions to be relevant (98%). MEONF-II and MUST took 8.8 and 4.7 minutes to complete, respectively, and both were considered relevant and easy to finish. In addition, MEONF-II was thought to reveal problems that allows for nursing interventions. Conclusions The MEONF-II is an easy to use, relatively quick, and sensitive screening tool to assess risk of undernutrition among hospital inpatients, which allows for substituting BMI with CC in situations where measures of patient height and weight cannot be easily obtained. High sensitivity is of primary concern in nutritional screening and the MEONF-II outperforms the MUST in this regard.