The geoid model is a component of the national coordinate system. This paper presents the main concept and role of the geoid within geodesy and other geo-sciences. The fundamental differences between geoid and quasigeoid are given, since the decision of each country for the appropriate model depends on the choice of the official height system. Current (quasi)geoid determination methods are presented. The history of the geoid models determined for the territory of Slovenia are briefly described, and the main characteristics are outlined for each solution. At the end, preparatory work performed in the frame of the project of the establishment of the new national spatial coordinate system within the field of a new geoid model determination are presented.

Key words: geoid, quasigeoid, heght reference surface, geoid determination, vertical component of the national spatial coordinate system