10 10 65 The CTEQ4m set of parton distribution functions (PDF) describes the momentum distributions of quarks and gluons in the proton and the antiproton. The variation ranges of x, Q variables are 10^-5 < x < 1 1.6 GeV < Q < 10000 GeV If the Monte Carlo sample point is out of this range, an extrapolation of the PDF is used. Warning is displayed for every case. The CTEQ4m set of PDF includes the Q-dependence calculated in the NLO approximation within the MSbar scheme, Alpha_s(MZ)=0.116 See details in H.L.Lai, J.Huston, S.Kuhlmann, F.Olness, J.Owens, D.Soper, W.K.Tung, H.Weerts, Phys.Rev. D55 (1997) 1280