Objetive: To evaluate, over a 79.2-month follow-up period, the behavior of bone mineral density (BMD) determined by Computerized Axial Densitometry (DXA), volumetric bone mineral density (BMDvol) and its relationship with anthropometric data, together with the parameters related to bone metabolism (calcium, phosphorus, alkaline phosphatase, parathormone (PTH) and vitamin D (25-OH-D3)) in a child population with Type 1 Diabetes Mellitus (DM1) without microvascular complications and a control group of reference with similar characteristics. Material and methods: Initially, a cross-sectional study was carried out in 40 diabetic children (mean age 9.4±2.8 years) and 108 controls (9.3±1.5 years) to assess the possible differences between the two populations. 26 patients from the initial diabetic group were reassessed after 79.2 months of follow-up. Results: It was observed that, at baseline, bone mass was similar in diabetics and controls. After follow-up, the BMD of the diabetic children was much lower than that expected in the non-diabetic child population. Weight, height, and Body Mass Index (BMI) followed the same pattern as BMD. The values of calcium, phosphorus, alkaline phosphatase, PTH and vitamin D, although within the normal range, were lower than in the controls. Alkaline phosphatase did not increase in the pubertal period. Conclusions: The present study demonstrates that children and adolescents with a recent diagnosis of DM1 have a normal BMD. However, over time, and especially during adolescence, they show less bone mass gain and changes in bone turnover parameters.