Zinc supplementation is an added intervention with oral rehydration solution (ORS) for treating childhood diarrhea as per World Health Organization recommendations. Our study aimed to determine the prevalence of zinc administration in addition to ORS for childhood diarrhea before hospitalization and the nutritional profile of those children admitted to the outpatient department of the largest diarrheal facility in Bangladesh. This study used a screening dataset of a clinical trial (www.clinicaltrials.gov; NCT04039828) on zinc supplementation at a Dhaka hospital (International Centre for Diarrhoeal Disease Research, Bangladesh) between September 2019 and March 2020. A total of 1,399 children aged 3-59 months were included in our study. Children were divided into two groups (one group received zinc and another did not) and were analyzed accordingly; 39.24% (n = 549) children received zinc along with ORS for the current diarrheal episode prior to hospitalization. Percentages of underweight (weight-for-age z-score < -2 SD), stunting (length/height-for-age z-score < -2 SD), wasting (weight-for-length/height z-score < -2 SD), and overweight (weight-for-age z-score > +2 SD) among these children were 13.87% (n = 194), 14.22% (n = 199), 12.08% (n = 169), and 3.43% (n = 48), respectively. In logistic regression after adjusting age, sex, and nutritional status (underweight, stunting, wasting, and overweight), association of dehydration (adjusted odds ratio [aOR]: 0.06; 95% CI: 0.03-0.11; P < 0.01), bloody diarrhea (aOR: 0.18; 95% CI: 0.11-0.92; P < 0.01), and fever (aOR: 0.27; 95% CI: 0.18-0.41; P < 0.01) were less with children who received zinc at home. Bangladesh is one of the leading zinc coverage areas globally but lags behind the target for zinc coverage in diarrheal illness among under-five children. Policymakers should scale up and formulate guidelines with sustainable strategies to encourage zinc supplementation in diarrheal episodes in Bangladesh and elsewhere.