In the present work, the self-assembly of Cu, Ag and Au clusters and nanoparticles in mordenite channels was considered. It was revealed that Si/Al molar ratio and the experimental conditions are the key factors in nanospecies formation. Ag8 clusters can be easily assembled in the mordenite; copper demonstrates multiples reduced forms, while gold preferably forms nanoparticles with average diameter 7.5 nm and plasma resonance peak observed even in freshly prepared samples. The temperature increase up to 500ºC leads to aggregation of gold particles.