XML technologies provide that digitalization of national heritage relies on widely accepted standards. Beside the XML standardized way of text and picture digitalization, there is a similar way for multimedia digitalization. Special XML language, called SMIL (Synchronized Multimedia Integration Language) is used for the multimedia digitalization. This language is very convenient for the digitalization of national heritage like the custom, national dresses, popular national music etc. The SMIL capabilities in digitalization (its good and bad sides) are described shortly in this paper. Several specific examples demonstrating SMIL characteristics and possible using in digitalization of multimedia heritage are presented.