Introduction Malnutrition is defined as an imbalance between requirements and intake of energy and/or nutrients that affect the growth—physical and cognitive functions. It is a major public health problem worldwide especially in children under five years. It includes under-nutrition either stunting, wasting, or micronutrient deficiencies and overweight or obesity. Several nutritional screening tools had been designed to detect nutritional risk of hospitalized children at an early stage. There are six tools, however, there is no consensus on which is the best tool to be used. In clinical practice, the most frequently used screening tools are: Screening of Risk for Nutritional Status and Growth (STRONGkids) and the Subjective Global Assessment of Nutritional Status (SGA). The study aimed to assess the nutritional status of hospitalized children at the time of admission and to evaluate the usefulness of STRONGkids. Patients and Methods A cross sectional study was conducted in Benghazi Medical Center (BMC), from July 2020 to November 2020. A total of 116 under five children admitted to the hospital were included in the study. Result and Discussion The study showed that 53.45% of children were males and 46.55% were females and showed that by using STRONGkids score, 42.2% of children were at low risk of malnutrition, 50.0% at medium risk, and 7.8% at high risk. There was an accordance between result of STRONGkids and weight for age, p = 0.000, similarly for height for age and weight for height. conclusion The STRONGkids screening tool could be used as an initial screening tool for children on admission to provide the right intervention at the right time.