Abstract Background and Aims Multidisciplinary guidelines recommend parathyroidectomy to slow the progression of chronic kidney disease in patients with primary hyperparathyroidism (PHPT) and an estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2. However, this is a weak recommendation, based on low-quality evidence. The objective of this study was to evaluate the estimated glomerular filtration rate change 12 months after parathyroidectomy for primary hyperparathyroidism according to preoperative kidney function. Method Patients who underwent parathyroidectomy for PHPT between 2017 and 2020 were retrospectively enrolled (n = 90). Patients without 1-year follow-up or with missing data were excluded (n = 42). Patients were dichotomized according to their baseline eGFR: < 60 mL/min (group 1; n = 13) and ≥60 mL/min (group 2; n = 35). Variables were measured before and then at 12 months after parathyroidectomy. Statistical analyses was made using SPSS 28. Results The cohort included 38 female patients (79.2%) with a mean age of 68.4 ± 11.27 years. Hypertension was present in 36 patients (75%) and 16 patients (33.3%) were diabetic. Thirty-two patients were being treated with ACEI/ARAII. The mean baseline eGFR was 44.6 ± 9.5 mL/min and 88.0 ± 12.7 mL/min in groups 1 and 2, respectively. Group 1 patients had a higher median baseline serum parathyroid hormone level (p = 0.002). At 12 months, all patients were normocalcemic. The eGFR decreased significantly after parathyroidectomy in group 2 (−5.8 mL/min, p = 0.012), while in group 1 the eGFR remain stable (−0.46 mL/min, p = 0.931). We didn't find any predictive factor of eGFR variation. Conclusion Further studies are needed to understand the progression of renal disease after parathyroidectomy. The etiology of the disease, the use of nephroprotective measures or in the other hand nephrotoxins may have an higher impact than restore normocalcemia alone.