[en] In this paper parity violation in the nucleon-nucleon interaction at low and intermediate energies is described in terms of a meson exchange model involving π, ρ and ω mesons, with one strong and one weak vertex. Experiments have yielded significant but incomplete information on weak meson-nucleon couplings, which are in qualitative agreement with predictions based on the Standard Model. An experiment currently underway at TRIUMF will determine the helicity dependence of the p-p scattering cross section at 222 MeV to ± 2 x 10^-8 or better, yielding an experimental constraint on the weak ρ-nucleon coupling to ± 30%, as compared with a theoretical uncertainty of ± ∼ 100%