Abstract: In this paper,we  show that there cxist preisely W(A)Ferrers matrices F(c₁,c₂,…,c_n) such that the rcok polynomials is equal to the nook palynomial of Ferrers matrix F(b₁,b₂,…,b_m), where   A={b₁,b₂-1,…,b_m-m+1l   is    a   rupeated    set,W(A)is    weight   of   A. 

Key words: rook polynomial, Ferrers matrix, repeated set