The understanding of the pathophysiology and the monitoring of metastatic bone disease remain unsatisfactory. Therefore, this study aimed at identification of the relationship between serum prolactin [PRL] levels and some bone metabolic markers [osteocalcin [OC], serum alkaline phosphatase [SAP], calcium [Ca], and inorganic phosphorus [Pi]] in early stages of breast cancer. Thirteen breast cancer patients in whom serum prolactin [PRL] levels had been determined were stratified into 2 groups according to their serum prolactin levels. Breast cancer I [BCI] included those with normal levels. Also a control group matched for age was taken. The bone markers of these groups were analyzed and compared. The study demonstrated that 6 patients [46%] “BCI" had a hyperprolactinemia and 7 patients “BCII" had a normal level of PRL. One way ANOVA test revealed significant differences in PRL, OC, SAP, Ca, and Pi between the three groups. OC is significantly reduced in the hyperprolactinemic patients reflacting diminished bone formation. SAP and Pi were significantly higher in all patients of breast cancer than that of the controls. The level of Ca tended to be higher in hyperprolactinemic patients than that of the controls. In the breast cancer patients, negative correlation between PRL and OC [r= -0.56, p < 0.05] was found. On the contrary, positive correlation between PRL and SAP [r=0.60, p < 0.05] was detected. It was concluded that the role of PRL in bone metabolism must be taken into consideration. Further wide scale studies are needed in a trial to uncover the exact role of hyperprolactinemia in patients with bone metastasis. This study could help in understanding bone disorders that may occur in breast cancer patients especially those with hyperprolactinemia.