AbstractCell–cell adhesion mediated by cadherins is essential for the function of bone forming cells during osteogenesis. Here, the evidence that N‐cadherin is an important regulator of osteoblast differentiation and osteogenesis is reviewed. Osteoblasts express a limited number of cadherins, including the classic N‐cadherin. The expression profile of N‐cadherin in osteoblasts during bone formation in vivo and in vitro suggests a role of this molecule in osteogenesis. Functional studies using neutralizing antibodies or antisense oligonucleotides indicate that N‐cadherin is involved in the control the expression of osteoblast marker gene expression and differentiation. Cleavage of N‐cadherin during osteoblast apoptosis also suggests a role of N‐cadherin‐mediated‐cell–cell adhesion in osteoblast survival. Hormonal and local factors that regulate osteoblast function also regulate N‐cadherin expression and subsequent cell–cell adhesion associated with osteoblast differentiation or survival. Signaling mechanisms involved in N‐cadherin‐mediated cell–cell adhesion and osteoblast gene expression have also been identified. Alterations of N‐cadherin expression are associated with abnormal osteoblast differentiation and osteogenesis in pathological conditions. These findings indicate that N‐cadherin plays a role in normal and pathological bone formation and provide some insight into the process involved in N‐cadherin‐mediated cell–cell adhesion and differentiation in osteoblasts. J. Cell. Physiol. 190: 297–305, 2002. © 2002 Wiley‐Liss, Inc.