Vitamin D is a crucial hormone in phosphocalcium homeostasis. Although vitamin D intoxication is rare, its complications can be dramatic, affecting both the short-term vital prognosis and long-term renal function. We report here a case of hypercalcemia due to vitamin D intoxication, with the aim of analyzing the factors that contribute to vitamin D intoxication, assessing the consequences of this intoxication on the child's health, and proposing recommendations for appropriate management. The patient was a 6-year-old child with a history of common nutritional rickets for which he had been receiving vitamin D supplementation. The patient was admitted to the pediatric emergency department of Children's Hospital in Rabat for incoercible vomiting and acute dehydration. Biological assessment showed severe hypercalcemia at 150mg/l, hypercalciuria at 192 mg /24 hours. The serum level of 25(OH) vitamin D was greater than 154 ng/ml. The diagnosis retained was as hypercalcemia due to vitamin D intoxication, confirmed by an in-depth interview with the parents, who found a over administration of the recommended dose. The evolution was marked by chronic kidney disease due to nephrocalcinosis (creatinine clearance according to the SCHWARTZ formula 17 ml/min). Heterogeneity of the expression forms of vitamin D dosages and intake regimens leads to confusion and increases the risk of misuse, as in the case of our patient, where a misreading of the medical prescription led to the intentional ingestion of toxic doses, hence the need for close and adequate medical supervision and awareness of vitamin D supplement use among healthcare professionals and parents.