"Tirgan" is an ancient Iranian festival. The Iranians celebrated it gloriously from the time of the Ma'ad era throughout Iran. After the Mahmous Afghan invasion, and for some still unknown reasons, "Tirgan" was forgotten. Now it is only celebrated among Zoroastrians, Armenians as well as some villages in the provinces of Guilan, Khorasan, and Mazandaran ; it is called "Tirmah Sizdahshoo"(The thirteenth night of the month of Tir)among the latter groups. One of the things that the people who participated in it did was splashing water on each other. Most Iranians do not know about "Tirgan" Festival and its old history. For reviving and also fostering a better understanding and familiarity with this ancient Iranian celebration the current research work was carried out.