ABSTRACT.In this paper, we introduce the notion of a fuzzy bi-quasi interior ideal as a generalization of fuzzy ideals, fuzzy bi-quasi ideals, fuzzy quasi-interior ideals and fuzzy bi-interior ideals of a semiring. We prove that every fuzzy right quasi-interior ideal of a semiring is a fuzzy bi-quasi interior ideal and a fuzzy bi-quasi interior ideal is a fuzzy right tri-ideal of a semiring. We characterize the regular semiring in terms of fuzzy bi-quasi interior ideals and study some of the properties.