A neutron spin echo (NSE) experiment was performed in order to clarify the droplet density dependence of the dynamic structures in a ternary microemulsion system consisting of AOT, water and decane. At the droplet concentration, &fgr;, of 0.05, the dynamic mode due to the peanuts‐like deformation of water droplets and the translational diffusion of them were analyzed, and the estimated decay time for the droplet deformation was about 10 ns. At &fgr; = 0.3, another dynamical mode due to the packing properties of water droplet is expected to be observed. Assuming that the deformation motion of the water droplets was independent of &fgr;, the dynamical mode due to the structure factor was estimated. The order of the decay time was one order of magnitude larger than that of the droplet deformation, and was smaller than that of the translational diffusion. © 2004 American Institute of Physics