In polycation-modified SDS/decanol systems, dense multilamellar structures, i.e. multilamellar vesicles are formed by self-organization, which were used as an organic template for CdS nanoparticle preparation. Specific amounts of precursors, CdCl
S, were incorporated into the multilamellar vesicles without losing the multilamellar structure. Structural changes of the lamellar liquid crystalline template induced by the incorporation of the polycation and the inorganic precursors were investigated by differential scanning calorimetry in combination with small angle X-ray scattering. By mixing both precursors within the multilamellar vesicles CdS nanoparticles are formed. After decomposition of the vesicle template, quite different shaped and sized CdS-nanoparticles were observed by transmission electron microscopy. At lower polymer concentration spherical CdS nanoparticles of about 10 nm can be obtained. At higher polymer concentration predominantly rod-like CdS aggregates were produced with an average length of 120 nm and width of 30 nm.