[en] The thermodynamic activities of Cd in liquid Cd-In-Tl alloys have been determined by the application of the isopiestic method. The entire field of concentrations has been covered at temperatures of 500, 550, 595, 650 and 700⁰C. The positive deviations of the activity isotherms from Raoult's law are indicating a prevailing tendency for demixing throughout the system. Nevertheless, a more detailed consideration of the partial and integral free excess enthalpies, of the enthalpies of mixing and of the excess entropies, as resulting from the fundamental experimental values leads to the conclusion that - similar to the conditions in the bordering systems Cd-In and Cd-Tl - there are also individual bonding influences in the ternary case: In spite of the general demixing tendency due to the differences of the atomic volumes of the component species this tendency is considerably reduced in the concentration area of about 75 at.-% Cd. (orig.)