ENThis article analyzes traditions of students’ 100 days party during 1924– 2015 years. Article is based on the material of the interwar period schools chronicles that were written during the Soviet period, student journal material, collected memories of students and teachers that helped reveal the features of 100 days’ party attributes and identify fundamental changes of this celebration in 90 years. The results showed that Kaunas Aušra gymnasium is the originator of 100- days parties in Lithuania, which have been celebrated since 1926. During the interwar period festival did not have enough time to become popular throughout Lithuanian schools. 100-days party celebration took place in two stages – we can distinguish the formal and informal part of the celebration. Both of these parts were celebrated in the school’s hall. At the official part graduates were able to showcase their talents – recite poems, sing songs, play performances. During unofficial part of 100-days party graduates and their teachers could get cozy evening together. 100-days party official part, it’s structure, time, place, participants remained almost unchanged during the Soviet era, restored independence period, it hadn’t changed to the present day. Changing times changed the unofficial part of the 100-days party celebration the most. In the twentieth century Unofficial 100-days party was celebrated in the school’s hall, but in the twenty-first century an increasing number of graduates choose to celebrate it in restaurants, cafes and nightclubs. School uniforms were replace by highly ornate clothing – boys wear suits and girls wear evening or cocktail dresses. 100-days party is the most important holiday, which prompted significant preparation time and costs. During 100 days party gifts are given. For the graduates a specific certificate and calendars were given.It should be noted that those certificates were more popular in Soviet times. In the twenty-first century certificates are replaces by short, funny videos, that most recent graduates creates, to deliver and to ridicule their classmates. During this feast schools are decorated abundantly – the most popular decorations are balloons, paper cuttings, which are closely related to the main theme of 100-days party performances.