AIM: Osteoporosis is a common long-term complication of type 1 diabetes (T1DM). We aimed to determine whether bone mineral density (BMD) and turnover are already altered during childhood. PATIENTS AND METHODS: We recruited 27 T1DM children and 32 controls (age 10.5 +/- 2.5 yr.) and measured BMD (dual-energy x-ray absorptiometry); bone biomarkers levels (osteocalcin: OC; procollagen type 1 propeptides amino-terminal: PINP; crosslinking telopeptides of type 1 collagen C-terminal: CTX), glycated hemoglobin (HbA1c), dietary intake and physical activity. RESULTS: Patients with T1DM had lower levels of OC (70.3 +/- 3.3 vs 105.3 +/- 6.8), PINP (556.4 +/- 47.6 vs 716.3 +/- 53.8), CTX(0.97 +/- 0.07 vs 1.20 +/- 0.08), physical activity, and calcium intake. Biomarkers were negatively correlated with HbA1c. Though, BMD was similar among groups and not related to HbA1c, disease duration, physical activity or dietary intakes. CONCLUSIONS: Bone turnover is altered in T1DM children, whereas BMD remains normal during growth. Physical activity and optimal calcium intakes may improve bone metabolism and delay osteoporosis.