We have calculated differential, integral, momentum transfer, and partial cross sections for elastic scattering and rotational excitation of C 2H2 by 10 eV electrons. The effective potential includes static, exchange, and polarization interactions calculated by the INDOX/1s method and the semiclassical exchange approximation with adiabatic polarization at large electron-molecule distances. The scattering is treated by well converged rotational close coupling using the centrifugal dominant scheme to select the channels included and including up to 32 coupled channels for a given total angular momentum. The calculated integral cross sections for pure elastic scattering and rotational excitation are 54.5 and 41.4a0 2, respectively. These are much larger than the values (34.4 and 18.6a02) previously [K. Onda and D. G. Truhlar, J. Chem. Phys. 71, 5107 (1979)] calculated for the isoelectronic molecule N2 at this energy. This illustrates how the greater spatial extent of C 2H2 greatly increases the cross sections for pure elastic and rotationally inelastic scattering.