The $\alpha_{s}$ dependence of parton distributions

We perform next-to-leading order global analyses of deep inelastic and related data for different fixed values of \alpha_S (M_Z^2). We present sets of parton distributions for six values of \alpha_S in the range 0.105 to 0.130. We display the (x, Q^2) domains with the largest parton uncertainty and we discuss how forthcoming data may be able to improve the determination of the parton densities