Context <p>It is unclear about the prevalence and risk factors of renal complications in childhood-onset patients with non-surgical hypoparathyroidism (ns-HP), which significantly hinders the clinical management and prognosis improvement.</p> Objective <p>To investigate the prevalence and risk factors of chronic renal complications in childhood-onset ns-HP patients receiving conventional therapy.</p> Design and setting <p>A retrospective cohort in childhood-onset patients with ns-HP at a tertiary care center, between 1977 and 2022.</p> Patients and methods <p>Childhood-onset ns-HP patients who received conventional treatment and were followed for at least 1 year were enrolled. Kaplan-Meier survival analysis and Cox regression were performed to identify the risk factors of renal complications. Time-dependent ROC curves were utilized to explore their optimal cutoff values.</p> Results <p>A total of 143 patients were enrolled in our cohort. Excluding 6 cases with pre-existed RC, 29/137 (21.17%) cases developed renal calcification (RC) during follow-up of 11.5 ± 8.5 years. Compared with patients without RC, they had a higher proportion of hypercalciuria (52.69 ± 32.8% vs. 35.64 ± 25.84%, <i>P</i> = 0.015) and renal insufficiency (RI) (17.24% vs. 3.70%, <i>P</i> = 0.021). Serum calcium-phosphate product (Ca×PO₄) (HR = 1.205, <i>P</i> = 0.033) and hypercalciuria proportion (HR = 1.048, <i>P</i> = 0.043) were independent risk factors for RC, with optimal cutoffs of 41.96&#xa0;mg²/dL² (AUC = 0.735) and 60% (AUC = 0.697), respectively. RI occurred in 6.29% (9/143) of patients, and the highest serum TCa during treatment (HR = 7.277, <i>P</i> = 0.019) was the risk factor of RI.</p> Conclusion <p>To reduce RC risk in childhood-onset ns-HP patients on conventional treatment, it is essential to consistently control the serum Ca×PO₄ and urinary calcium excretion. Hypercalcemia during the treatment should be avoided to prevent RI.</p>