Massimo Campanino and Dmitry Ioffe Ornstein-Zernike theory for the Bernoulli bond percolation on $Z^d$. (341K, postscript) ABSTRACT. We derive precise Ornstein-Zernike asymptotic formula for the decay of the two-point function $P(0\lra x)$ of the Bernoulli bond percolation on the integer lattice $Z^d$ in any dimension $d\geq 2$, in any direction $x$ and for any sub-critical value of $p < p_c (d)$.