In this paper, we considered some properties and characterizations of fuzzy  – ideals such as fuzzy interior  – ideals and fuzzy bi  – ideals of  – semi groups and investigate some of their properties. We also have studied fuzzy quasi  – ideals and fuzzy left (right, two sided)  – ideals of  – semi groups.

Keywords :  -Semi Group, Fuzzy bi  – Ideal, Fuzzy Quasi  – Ideal, Fuzzy Interior  – Ideal.