INTRODUCTION: Growth Hormone Deficiency (GHD) is a rare disease marked by a complete or partial reduction in the production of growth hormone. Vitamin D deficiency is frequent and may be associated with several pathologies. However, the association between GHD and vitamin D deficiency has not been extensively studied. This study aimed to analyse VDR gene polymorphisms related to vitamin D status to ensure better care for patients with GHD. MATERIAL AND METHODS: A case-control study was conducted at the Children's Hospital of Tunis in collaboration with the Farhat Hached's Hospital of Sousse, including patients with GHD and healthy subjects. Genetic analysis of the VDR gene polymorphisms was performed using PCR-RFLP technique. Haplotypes were examined with Haploview software, while statistical analyses were carried out using SPSS and R programming language. RESULTS: Our study revealed significant differences in vitamin D (p = 0, 049) and calcium concentrations between patients and healthy subjects, which were lower in the GHD group (p = 0,018). A comparison of allelic and genotypic frequencies of the five polymorphisms indicated an association between the I polymorphism and GHD. Furthermore, significant difference was observed between the I genotypes and PTH (p = 0,019) and ALP (p = 0,035). I genotypes were associated with phosphorus (p = 0,021). Additionally, One haplotype, CTAGT, exhibited a significant difference between the patients and healthy subjects (p = 0,002). CONCLUSION: Our study findings indicate that hypovitaminosis D is common among patients with GHD, even when undergoing treatment with rhGH. This underscores the critical importance of vitamin D supplementation during treatment.