The aim of this study was to determine whether the plasma CTX bone remodeling marker is useful for indicating the bone metabolic activity level of the mandible. Thirty-six patients were selected; all were postmenopausal and aged 50 years or over. In accordance with the WHO criteria for osteoporosis, a control group was set up (n = 10) in which the T-score was greater than -1 and a diseased group with Tscore less than -1. Using MDP-99m Tc samples, the radioisotope uptake in the femoral neck (R 2 ) and mandibular body (R 1 ) was analyzed. A third examination was performed using the plasma CTX biochemical bonemodeling marker. The inferential results for the diseased group showed that Ln(R 1 ) presented a statistically significant linear relationship with Ln(CTx) (p = 0.067) and with the T-score (p = 0.018). The plasma CTX bone remodeling marker is useful for monitoring the bone metabolic activity of the mandible.