Diabetic ketoacidosis (DKA) is a common acute complication of type 1 diabetes mellitus (T1DM). DKA is characterized by hyperglycemia, metabolic acidosis, increased levels of ketone bodies in blood and urine. This leads to osmotic diuresis and severe depletion of water and electrolytes from both the intra- and extracellular fluid (ECF) compartments. Estimation of the degree of dehydration for children admitted with DKA is of great clinical importance. The calculation of the amount of deficit therapy depends on the estimated degree of dehydration. However, the degree of dehydration present during DKA is difficult to be clinically assessed. Hyperosmolality tends to preserve intravascular volume with maintenance of peripheral pulses, blood pressure, and urine output until extreme volume depletion occurs. Metabolic acidosis leads to hyperventilation and dry oral mucosa as well as decreased peripheral vascular resistance and cardiac function . consequently, hyper-osmolality may lead to an underestimation of the degree of dehydration, whereas metabolic acidosis may lead to an overestimation of the degree of dehydration. This makes the physical findings unreliable in this setting. Several clinical and biochemical markers were suggested to assess and stage the degree of dehydration at hospital admission. The blood urea nitrogen , hematocrit , plasma albumin are useful markers of the degree of ECF contraction.However, Several previous studies demonstrated that there was no agreement between assessed and measured degree of dehydration which is calculated according to change in body weight at admission and after correction of dehydration. there were tendencies to overestimated or underestimate the degree of dehydration between different physicians. The assessment of the magnitude of dehydration in DKA is of major interest and continues to be a subject of research. This study aims to assess the association between different clinical and laboratory parameters in children with diabetic ketoacidosis and the degree of dehydration at hospital admission among those children.