A list Λ = {λ 1 , λ 2 , . . . , λ n } of complex numbers is said to be realizable if it is the spectrum of an entrywise nonnegative matrix. In this paper we intent to characterize those lists of complex numbers, which are realizable by a centrosymmetric nonnegative matrix. In particular, we show that lists of nonnegative real numbers, and lists of complex numbers of Suleimanova type (except in one particular case), are always the spectrum of some centrosymmetric nonnegative matrix. For the general lists we give sufficient conditions via a perturbation result. We also show that for n = 4, every realizable list of real numbers is also realizable by a nonnegative centrosymmetric matrix.{λ 1 , λ 2 , . . . , λ n }. If there exists an n × n nonnegative matrix A with spectrum Λ we say that Λ is realizable and that A is the realizing matrix. A complete solution for the NIEP is known only for n ≤ 4, which shows the difficulty of the problem. Throughout this paper, if Λ = {λ 1 , λ 2 , . . . , λ n } is realizable by a nonnegative matrix A, then λ 1 = ρ(A) = max{|λ i | , λ i ∈ Λ} is the Perron eigenvalue of A. We shall denote the transpose of a matrix A by A T , ⌊x⌋ and ⌈x⌉ denote the largest integer less than or equal to x and the smallest integer greater than or equal to x, respectively. J will denote the counteridentity matrix, that is, J = [e n | e n−1 | · · · | e 1 ]. Then it is clear that J T = J, J 2 = I. Observe that multiplying a matrix A by J from the left results in reversing its rows, while multiplying A by J from the right results in reversing its columns. A vector x is called symmetric if Jx = x.The set of all n × n real matrices with constant row sums equal to α ∈ R will be denote by CS α . It is clear that e = [1, 1, . . . , 1] T is an eigenvector of any matrix in CS α , corresponding to the eigenvalue α. The relevance of matrices with constant row sums is due to the well known fact that the problem of finding a nonnegative matrix A with spectrum Λ = {λ 1 , . . . , λ n } is equivalent to the problem of finding a nonnegative matrix B ∈ CS λ 1 with spectrum Λ, that is, A and B are similar if the Perron eigenvalue is simple and they are cospectral otherwise (see [4]).In this paper we study the NIEP for centrosymmetric matrices. Centrosymmetric matrices appear in many areas: physics, communication theory, differential equations, numerical analysis, engineering, statistics, etc. Now we state the definition and certain properties about centrosymmetric matrices.Definition 1.1 A matrix C = (c ij ) ∈ M m,n is said to be centrosymmetric, if its entries satisfy the relationThe definition means that a centrosymmetric matrix C can be written as J m CJ n = C, where J n is the n × n counteridentity matrix. That is, J n = [e n | e n−1 | · · · | e 1 ] . For m = n, we shall write J instead J n .