Patients with high-output small bowel ostomies are at risk for total body sodium depletion (TBSD), defined as a urine sodium level <10 mmol/L. Failure to thrive (FTT) as a consequence of TBSD has been reported in neonates with ileostomies; however, this has not been well described in older children. The records of all children beyond the age of infancy with a small bowel ostomy cared for in our Children's Intestinal Rehabilitation Program from 2010-2012 were reviewed. Four patients between the ages of 18 months and 19 years were identified as having TBSD. All 4 patients experienced unintentional weight loss, despite adequate energy intake based on calculated needs, which was associated with a urine sodium level ≤10 mmol/L. With the supplementation of sodium, either enteral or intravenous, all patients demonstrated improved weight gain and correction of TBSD. The following cases suggest that the relationship between TBSD and FTT may extend well beyond the neonatal period and possibly into adulthood. We advise that patients of all ages with high stoma output have routine urine sodium levels checked, particularly in the setting of weight loss or poor gain. Furthermore, instances of TBSD should be treated with sodium supplementation. Further research is needed to better understand the relationship between TBSD and FTT and to establish intervention guidelines.