The influence of duration of diabetes and metabolic control on phalangeal quantitative ultrasound (QUS) was evaluated in a group of children and adolescents with type 1 diabetes. Eighty-six patients (mean age 11.9 years; mean duration 4.3 years) were studied. Daily calcium intake was assessed by means of a questionnaire. Amplitude-dependent speed of sound (AD-SoS) was measured at the phalanxes of the non-dominant hand and expressed as a z-score. Linear and multivariate correlations with duration of diabetes and, short term and long term metabolic control were sought. AD-SoS z-score was -0.43+/-1.4 (95% CI, -0.73; -0.13). Nine subjects had values below -2S.D. Daily calcium intake was 1042+/-456 mg/day; 47 subjects (54.6%) were below the recommended levels. A negative correlation was found between AD-SoS z-score and duration (r, -0.33, P=0.002) or metabolic control (HbA1c-last year r, -0.32, P=0.002; HbA1c-whole duration, r, -0.40; P=0.003). Negative AD-SoS z-scores depended significantly and directly on duration and quality of metabolic control, even when controlled for calcium intake. In conclusion, the architectural organization of bone was impaired in 10.5% patients. Duration of diabetes and poor metabolic control were the main determinants affecting AD-SoS. QUS may be a useful tool in the screening of bone disturbance in young patients with diabetes. Optimization of metabolic control is required to prevent osteoporosis.