Chronic kidney disease (CKD) is associated with an increased risk of bone mineral density (BMD) loss, leading to fractures and osteoporosis. ɑ-Klotho, a circulating protein with potential protective effects on bone metabolism, has been suggested to influence BMD. However, its role in BMD decline among CKD patients remains unclear. This study investigates the association between ɑ-Klotho levels and the rate of BMD decline. A total of 1,185 CKD patients were included in this longitudinal study. BMD measurements were obtained at baseline and after four years. The associations between serum ɑ-Klotho levels at baseline and the BMD decline rate was assessed using multiple linear regression models. To determine the interaction between time and ɑ-Klotho, we included a year*log ɑ-Klotho interaction term in the model. The baseline-adjusted analysis demonstrated that BMD declined significantly over time (β = -3.448 per year, 95% CI: -5.494 to -1.401, p < 0.001). The year*log ɑ-Klotho interaction term showed a significant positive association with BMD decline rate (β = 0.463, 95% CI: 0.134 to 0.791, p = 0.0058), suggesting that higher ɑ-Klotho levels were associated with a slower rate of BMD loss. Visual analyses confirmed a dose-dependent relationship, with higher ɑ-Klotho tertiles exhibiting less BMD decline rate. This study provides that higher ɑ-Klotho levels are associated with a reduced rate of BMD decline in CKD patients. These findings highlight the potential role of ɑ-Klotho in bone health preservation and suggest that it may serve as a biomarker or therapeutic target for managing CKD-related bone loss.