Single- and double-walled magnetic nanotubes are obtained in a one-step liquid phase reaction by the cooperative self-assembly of chiral amphiphiles and nanoparticles on cooling of heated mixtures of N-dodecanoyl-L-serine and Fe₃O₄ nanoparticles in toluene. The nanotubes are composed of well-ordered, close-packed nanoparticle assemblies, and can be transformed into chiral magnetic nanostructures, such as helical coils, by subsequent calcination. The nanoparticle assemblies and their variations on calcination are attributed to the collective organization of the surfactant molecules adsorbed on the nanoparticles and the freely dispersed chiral molecules, and the dewetting effects guided by the primitive constitution of the chiral amphiphilic molecular assemblies.