A member of the ${R}_{3}{\mathrm{MO}}_{7}$ family containing two magnetic cations, ${\mathrm{Gd}}_{3}{\mathrm{RuO}}_{7},$ has been synthesized by high-temperature solid-state reaction. The structure has been determined by single-crystal methods: space group $\mathrm{Cmcm}(#63),$ ${a}_{0}=10.643(2)\AA{},$ ${b}_{0}=7.345(1)\AA{},$ ${c}_{0}=7.380(1)\AA{},$ $V=576.90(14){\AA{}}^{3},$ $Z=4,$ $R1=0.021,$ $\mathrm{wR}2=0.047.$ The most important structural feature is the one-dimensional ${\mathrm{RuO}}_{6}$ chain running parallel to the c axis. In a wide temperature range the conductivity of ${\mathrm{Gd}}_{3}{\mathrm{RuO}}_{7}$ follows the dependence $\mathrm{ln}(\ensuremath{\rho})\ensuremath{\propto}{T}^{\ensuremath{-}1/2},$ which is typical for Mott variable-range hopping of localized carriers in one dimension. The magnetic susceptibility obeys the Curie-Weiss law with ${\ensuremath{\theta}}_{p}=\ensuremath{-}7.5\mathrm{K}$ and Curie constant ${C}_{\mathrm{mol}}=25$ emu K/mole. Magnetization data reveal two successive transitions at about 14.5 and 8 K, which indicates independent ordering of Ru and Gd moments, respectively. The analysis shows that in total 27 ${(8A}_{g}{+8B}_{1g}{+5B}_{2g}{+6B}_{3g})$ Raman-active modes are expected for ${\mathrm{Gd}}_{3}{\mathrm{RuO}}_{7}.$ As a larger number of ${A}_{g}$ lines (10) are observed in the polarized Raman spectra, we suggest that two of the ${A}_{g}$ lines (at 233 and $780{\mathrm{cm}}^{\ensuremath{-}1})$ either arise from local vibrations or are of nonphonon origin.