Let , ∈ N with 1 ≤ ≤ and let Ω = Ω 1 × Ω 2 be an open set in R × R − . For ∈ (1, ∞) and ∈ (0, ∞), we consider the following weighted Sobolev type inequality:for some > 0. Depending on the values of , , , we have identified various pairs of Lorentz spaces, Lorentz-Zygmund spaces and weighted Lebesgue spaces for ( 1 , 2 ) so that (0.1) holds. Furthermore, we give a sufficient condition on 1 , 2 so that the best constant in (0.1) is attained in the Beppo-Levi space 1, 0 (Ω)-the completion of 1 (Ω) with respect to ‖∇ ‖ (Ω) .