Bilayer membranes and wormlike micelles have been studied using molecular–dynamics simulations. The structure of the worm is analysed in terms of radial density distribution functions, and mechanical properties such as the elastic modulus are calculated. From an analysis of the fluctuation spectra of the tensionless states, we have calculated bending rigidities. Micelles consisting of coarse–grained (CG) model surfactants are studied in order to map the properties of the atomistic micelle. We optimize the CG model with respect to the structure factor S(q) of the atomistic micelle. The mechanical properties thus obtained will be used as input for a mesoscopic model of wormlike micelles where the persistence length is the smallest length–scale.