The resistivity ρ (T) of the spin-ladder compound CaCu2 O3 measured along the Cu-O-Cu leg (jb) exhibits a strongly activated character. It increases from ∼ 104 to ∼ 109 m if T decreases from 350 to 100 K. The charge transfer above T∼200 K is governed by a quasi-one-dimensional (1D) nearest-neighbor hopping (NNH) conductivity mechanism characterized by the law ρ (T) ∼exp (Ea /kT). Below 200 K a novel quasi-1D variable-range hopping (VRH) conductivity law ρ (T) ∼exp [(T0 /T) 3/4] is observed, predicted recently by Fogler, Teber, and Shklovskii [Phys. Rev. B 69, 035413 (2004)]. The NNH activation energy Ea and the VRH characteristic temperature T0 exhibit high sensitivity to the cation (Ca, Cu) content, decreasing by 2.3-2.5 times and by 3.0-3.2 times, respectively, when the composition of Ca is changed from 0.854 to 0.786-0.798 and the composition of Cu from 2.039 to 2.159-2.163. The behavior of Ea and T0 can be attributed to a corresponding variation of the concentration of intrinsic defects associated with Cu vacancies. On the other hand, no direct dependence of Ea and T0 to the excess oxygen concentration is observed.