Introduction: Malnutrition is a common problem among hospitalized patients. In chronic kidney disease, it affects up to 50% of the population. Undernourishment has an adverse effect on prognosis and prolongs convalescence. The aim of the study was to test the effectiveness of NRS (Nutrition Risk Screening) -2002 in the assessment of risk of malnutrition for patients hospitalized in nephrology wards. The aim was to develop clinical characteristics of malnourished patients and to assess the relationship between nutritional status and patient outcome. Methods: The analysis included 292 patients, consecutively admitted to nephrology wards. NRS-2002 was assessed in comparison to subjective global assessment. Associations with patient characteristics and outcome were evaluated. Results: Out of all the respondents, 119 patients (40%) suffered from malnutrition. The NRS-2002 showed a very strong relationship with Subjective Global Assessment (SGA) ( p < 0.0001). Malnourished patients were older, were characterized by a significantly lower body mass index (BMI), and had a much longer hospitalization duration. In multiple regression analysis, the presence of malnutrition proved to be an independent predictor of the duration of hospital stay. CONCLUSIONS: Malnutrition is highly prevalent among patients hospitalized in nephrology wards, and it affects the length of hospitalization. Identification of malnourished patients and patients at serious risk of malnutrition progression allows the implementation of appropriate nutritional intervention.