In this work we firstly tested the influence of low molecular weight fucoidan extracted from pheophicae cell wall on bidimensional cultured normal human osteoblasts behaviours. Secondly impregnation procedure with LMW fucoidan of bone biomaterial (Lubboc®) we explored in this bone extracellular matrix context its capabilities to support human osteoblastic behaviour in 3D culture. In bidimensionnal cultures we evidenced that: LMW fucoidan promotes human osteoblast proliferation, collagen type I expression and favours precocious alkaline phosphatase activity. Furthermore with LMW fucoidan von Kossa's staining was positive at 30 days and only positive at 45 days in absence of LMW fucoidan. In our three dimensional culture models with the biomaterial pretreated with LMW fucoidan osteoblasts promptly overgrew the pretreated biomaterial. We evidenced too osteoblasts increased proliferation with pretreated biomaterial when compared with untreated biomaterial. On control as well as with LMW fucoidan impregnated biomaterial osteoblasts secreted osteocalcin and expressed BMP2 receptor. In conclusion, in our experimental conditions LMW fucoidan stimulated expression of osteoblastic markers differentiation such as alkaline phosphatase activity, collagen type I expression and mineral deposition, furthermore cell proliferation was favoured. These findings suggest that fucoidan could be clinically useful for bone regeneration and bone substitute design.