In vertebrate neuromuscular junction, acetylcholinesterase (AChE) is colocalized with acetylcholine receptor (AChR). This synaptic expression of AChE requires precise regulation of the AChE gene. However, the gene regulation pattern has species variation. Previous studies (Massoulié, 2002) indicated that AChE activities in muscles decreased in rat but increased in chicken after denervation. The spatial arrangement of regulatory elements in promoters among animals therefore might be varied. The genomic structures of AChE have been analyzed in Torpedo, mouse, rat, and human but not in chick, and the molecular mechanism(s) responsible for contrary regulation of AChE between chick and mammal has been proposed (Choi et al., 2001) but not fully understood. Here, we report the cloning of the chick AChE promoter, the regulation of which is being characterized.