The superconducting transition temperature Tc as well as the magnetic ordering temperature Tm have been determined in the mixed ternary compound ErxY1−xRh1.1Sn3.6 as a function of the Er concentration. Tc decreases from 3.13 K for YRh1.1Sn3.6 to 1.1K for ErRh1.1Sn3.6. Reentrant superconductivity has been found for x > 0.6. The application of the models of Abrikosov and Gorkov, Maekawa and Tachiki, and Roshen and Ruvalds to this system is discussed. Tc as function of the concentration x is best described by the model of Roshen and Ruvalds assuming a ferromagnetic interaction between the spins. The parameter I2N(0), arising from electron spin, is found to be 0.088 K. The ferromagnetic ordering temperature dependence is described by the theory of Oguchi and Ono, using an effective coordination number z = 6 and an exchange constant of J′ = 0.30 K.