Aim and objectives. To determine whether a modified version of the Mini Nutritional Assessment (MNA) without body mass index (BMI) can effectively identify individuals at risk of malnutrition among patients with neuropsychiatric disorders. Background. Neuropsychiatric patients have an additional risk of nutritional disorder due to functional impairments and drug effects. However, their nutritional status is generally neglected. It is important to find a tool that is simple, easy to use and noninvasive. Design. The study involved 105 patients in the acute phase of confirmed neuropsychiatric disorders in an area hospital. All subjects were cognitively able to have effective verbal communication. Method. The study included serum biochemical and anthropometric measurements and an on-site, in-person interview using a structured questionnaire to elicit personal data, health condition and answers to questions in the MNA. Subjects’ nutritional statuses were graded with a MNA that adopted population-specific anthropometric cut-off points or one further with the BMI question removed and its assigned score redistributed to other anthropometric questions. Results. Both versions of the modified MNA effectively graded the nutritional status of neuropsychiatric patients and showed good correlations with the major nutritional indicators such as BMI, calf circumference and the length of hospital stay. Conclusions. The MNA can effectively assess the nutritional status of neuropsychiatric patients and enhance timely detection and intervention of their nutritional disorders. A modified MNA without the BMI question can maintain the full functionality of the tool. The version does not require weight and height measurements and thus will enhance the usefulness of the instrument. Relevance to clinical practice. Neuropsychiatric patients are a high-risk group of nutritional disorders. The MNA, especially the one without BMI, has the potential to improve professional efficiency of the primary care workers.