A histomorphometric evaluation of the iliac crest trabecular bone remodeling was performed after tetracycline double-labeling in 41 normal Danes (12 males and 29 females) aged 19 to 56 years. The fraction of formative (osteoid covered) and resorptive surfaces was unrelated to age but higher in males than in females (P<0.02 and P<0.05, respectively). The appositional rate (0.65±0.12 μm/day) was unrelated to age and sex, whereas the fractional labeled surfaces were higher (P<0.01) in the males (0.18±0.08 μm²/μm²) than in the females (0.12±0.05 μm²/μm²), and among the females inversely related to age (R=−0.38,P<0.05). The bone formation rate at BMU level (0.50±0.20 μm³/μm²/day) was unrelated to sex, but among the females inversely related to age R=−0.49,P<0.01). The bone formation rate at tissue level was higher (P<0.02) in the males (0.13±0.07 μm³/μm²/day) than in the females (0.07±0.03 μ m³/μm²/day) and among the females inversely correlated to age (R=−0.43,P<0.05). The age- and sex-dependent variations in the dynamic parameters underline the importance of a more elaborated normal material.