Frequent occurrences of hypocalcemia were observed in patients with advanced chronic kidney disease (CKD stage 4-5D) receiving denosumab (Dmb) for the treatment of osteoporosis, however, little is known about risk factors of hypocalcemia in the patients with better kidney function. In this study, we attempted to identify risk factors for the decrements in serum corrected calcium (cCa) concentration among the patients with CKD stage 1-3. Seventy-four participants (age, 67.9 ± 11.9 years, eGFR 66.9 ± 16.2 mL/min/1.73m², mean ± SD; eGFR ranges 36-111 mL/min/1.73m²) received initial administration of 60mg Dmb with supplementation of calcium and native vitamin D₃. Previous osteoporosis treatments were bisphosphonates (44 cases), and SERM (14 cases). The cCa levels were rapidly and significantly decreased from day 3 after the administration, and reached a nadir on day 7 (9.0 ± 0.4 mg/dL), which was significantly lower than pre-administration (9.4 ± 0.3 mg/dL; p< 0.001). The multiple linear regression analysis revealed that baseline cCa, eGFR, log [TRACP-5b] and pretreatment by antiresorptive drugs such as bisphosphonates or SERM were significant factors independently associated with the absolute decrement in cCa from baseline to day 7 (ΔcCa_0-7day) (β= -0.4154, p= 0.0001; β= 0.2444, p= 0.0318; β= -0.2211, p= 0.0342; and β= 0.2174, p= 0.0368, respectively). Subsequently, a large decrease in cCa concentration post Dmb injection, defined as ΔcCa_0-7day> 1.0 mg/dL, was observed in 8 participants (10.8%). Multivariate logistic regression analysis identified the non-pretreatment of antiresorptive drugs (OR 19.2, 95%CI 1.56–78.9; p= 0.0012) and baseline eGFR less than 57 mL/min/1.73m² (OR 8.47, 95%CI 1.51–76.3; p= 0.0247) as independent risk factors for ΔcCa_0-7day> 1.0 mg/dL. In addition to eGFR, bone turnover was an independent risk factor for Dmb-induced decrement of cCa in CKD 1-3. Pretreatment by antiresorptive drugs was beneficial in reducing the risk of the decrement of cCa.