Objective:  The aim of this study is to assess the level of serum bone sialoprotein as a diagnostic biomarker in cases of diabetic bone diseases and its relation to diabetic microvascular complications. Methods:  A total of 60 subjects; 30 diabetic patients type II with micro-vascular complications (retinopathy and/or nephropathy) as a case group and 30 healthy individuals serve as control group was recruited in this case–control study from diabetes and endocrinology clinic and internal medicine department in Beni Suef university hospital. The biochemical and metabolic parameters and bone turnover marker will be assessed in all patients.  Results: Serum bone sialoprotein (BSP) was found to be significantly higher in diabetic patients with microvascular complication compared to normal control group. Moreover, bone sialoprotein (BSP) was positively correlated to osteoporosis of lumbar spine. Conclusion: Bone sialoprotein increase could be used as a biomarker of diabetic bone disease diagnosis and could be a predictor of spinal osteoporotic fractures in diabetic patients.