Children with malnutrition present with aberrant laboratory parameters. This study aimed to identify high-risk diarrheal children with varied nutritional status. The data were obtained from the electronic database of Dhaka Hospital, International Centre for Diarrhoeal Disease Research, Bangladesh from 2019 to 2021. Among 1,068 children under 5 years of age with diarrhea, 177 (14%) had severe acute malnutrition (SAM; weight-for-length/height Z score < -3), 239 children (17%) had severe stunting (SS; length/height-for-age Z score < -3), and 652 did not have malnutrition (weight-for-length/height and weight-for-age and length/height-for-age Z score > -2). We independently assessed the relationship of nutritional profiles with each clinical and laboratory parameter. After adjustment for age and sex in the multiple regression model, hyponatremia (adjusted odds ratio [aOR] = 2.37 [95% CI: 1.52-3.68]; P < 0.001) and dehydration (aOR = 2.42 [95% CI: 1.67-3.52]; P < 0.001) were independently associated with SAM compared with children without malnutrition. In comparison to non-malnutrition, SS was less likely to be associated with acute watery diarrhea (aOR = 0.66 [95% CI: 0.47-0.92]; P = 0.014) but was significantly associated with anemia (aOR = 2.18 [95% CI: 1.57-3.02]; P < 0.001) and thrombocytosis (aOR = 2.43 [95% CI: 1.78-3.32]; P < 0.001). The presence of hypernatremia was substantially lower in children with SAM (aOR = 0.38 [95% CI: 0.22-0.65]; P < 0.001) or SS (aOR = 0.56 [95% CI: 0.35-0.88]; P = 0.012) than in children without malnutrition. Severe stunting was less likely to be associated with dehydration (aOR = 0.44 [95% CI: 0.29-0.67]; P < 0.001) in contrast to SAM. Therefore, children hospitalized with diarrhea may have different clinical and laboratory manifestations depending on their nutritional status and may require differential treatment.