We study soft-gluon radiation for heavy quark production in charged-current Deep Inelastic Scattering processes. We resum large-x contributions to the MSbar coefficient function to next-to-leading logarithmic accuracy and present results for charm quark structure functions for several values of the ratio m_c/Q. The effect of the resummation turns out to be visible, especially at small Q^2, and the results exhibit very little dependence on factorization and renormalization scales. The impact of our calculation on structure function measurements at NuTeV and HERA experiments is discussed.