Purpose: To evaluate the complications encountered during microwave ablation (MWA) for primary and secondary hyperparathyroidism (HPT). Materials and methods: The retrospective study enrolled 213 secondary hyperparathyroidism (SHPT) and 51 primary hyperparathyroidism (PHPT) patients who received MWA between July 2015 and September 2018. The major and minor treatment-related complications were documented. The baseline data, clinical parameters, laboratory indices and characteristics of the parathyroid glands were analyzed to assess the risk factors associated with these complications. Results: The incidence of post-MWA complications in HPT patients was 12.1% (32/264). In total, five (5/264, 1.9%) patients with SHPT had major complications, including aphonia/hoarseness (n = 4) and Horner syndrome (n = 1). A total of 27 (10.2%, 27/264) HPT patients had minor complications, including neck hematoma (0.8%, 2/264), bucking (4.2%, 11/264) and phonasthenia (5.3%, 14/264). The incidence of severe hypocalcemia (SH) after MWA was 18.2%. Cutaneous necrosis occurred in two SH patients after intravenous calcium supplementation. There were no significant differences in the incidence of overall complications, major complications and minor complications between SHPT and PHPT patients (12.7% vs 9.8%, p = 0.811; 2.3% vs 0, p = 0.587; 10.3% vs 9.8%, p = 1.000). A history of parathyroidectomy (PTX) (p = 0.031) and multiple symptoms (p = 0.000) were risk factors for the occurrence of complications in SHPT patients. One patient sustained a permanent injury to a unilateral recurrent laryngeal nerve (RLN), and the two patients who experienced cutaneous necrosis underwent debridement plus autologous skin transplantation. The remaining patients recovered without sequelae. Conclusion: The incidence of major complications was low which only occurred in SHPT patients. Most of the patients with complications recovered spontaneously. MWA is safe for the treatment of HPT.