The amplitude of the coherent backscattering intensity peak is computed for a medium composed of densely packed, randomly positioned particles. The cyclical component of the Stokes reflection matrix at exactly the backscattering direction is expressed in terms of the ladder component, and the ladder component is rigorously computed by numerically solving the vector radiative transfer equation. The effect of packing density is accounted for by multiplying the singlescattering Mueller matrix by the static structure factor computed in the Percus–Yevick approximation. It is shown that increasing packing density can substantially reduce the amplitude of the copolarized coherent back scattering peak, especially for smaller particles, and can make it significantly lower than 2. The effect of packing density on the amplitude of the crosspolarized peak is significantly weaker.