[en] We have developed a new technique to directly measure ρ_c and ρ_ab of very small single crystals of Y₁Ba₂Cu₃O_7-x. We used this technique to measure ρ_c in two different crystals having different Tc's. In contrast with results obtained by the standard Montgomery method we find smaller values of ρ_c at 300 K, although the increase of ρ_c at T≥Tc is higher. Our data indicate the presence of localized states between the CuO₂ planes due to intrinsic or extrinsic ''dirty'' interlayers. The c-axis resistivity follows a thermally activated law lnρ_c∝(T₀/T) with T₀=410 K. A correlation is observed between the lowering of Tc and the increase of ρ_c at T≥Tc. (orig.)