Normative values for bone mass were assessed for whole body bone mineral content (WBBMC), anterior-posterior and lateral lumbar spine, radius, femoral neck, trochanter, and Ward's triangle bone mineral density in 778 healthy children and adolescents (433 females and 345 males) from 2–20 years of age from Argentina. Bone mineral content was assessed by dual energy X-ray absorptiometry (DEXA) (Norland XR-26 HS with dynamic filtration). All subjects were Caucasian. WBBMC maximum mean value for girls was found to be in the 16-year-old group with difference between gender becoming significant in the 17-year-old (p < 0.05) group. The femoral neck, trochanter, and Ward's triangle BMD values in females increased until 14 years of age, with no significant difference between age groups older than 13. In males, no difference between age groups was seen in groups older than 16 years of age. The radius BMD showed a mild increment through infancy and adolescence in boys and girls. In lumbar spine, the gender differences were significant only in those groups over 16 years old, with boys showing a greater BMD than girls (p < 0.001). When Tanner stage was considered, the anova analysis showed in males that there were significant differences between stages (1–2, 2–3, and 4–5 (p < 0.01), but no differences between stages 3–4 for all the sites. In females, there were significant differences between stages 1–2 and 2–3 (p < 0.01), but not between stages 3–4 and 4–5 for WBBMC, FNBMD and LSBMD. There were no significant differences between Tanner stages for RBMD values. The densitometric values presented are useful to assess bone mineral status in children and adolescents, allowing an improved approach to primary and secondary metabolic bone diseases.