Let θ be a root of a monic polynomial h(x) ∈ Z[x] of degree n ≥ 2. We say h(x) is monogenic if it is irreducible over Q and {1, θ, θ 2 , . . . , θ n−1 } is a basis for the ring Z K of integers of K = Q(θ). In this article, we study about the monogenity of number fields generated by a root of composition of two binomials. We characterise all the primes dividing the index of the subgroupm ≥ 1 and n ≥ 2. As an application, we provide a class of pairs of binomials f (x) = x n − a and g(x) = x m − b having the property that both f (x) and f (g(x)) are monogenic.