The superconducting transport properties of polycrystalline Tl2Ca2Ba2Cu3O10thin films irradiated with 740 keV oxygen ions were monitored as a function of fluence. Both the transition temperature (Tc) and the critical current density (Jc) decreased rapidly with fluence; however, the transition temperature onset remained constant. A fluence of 2×1014O/cm2(0.028 dpa) was sufficient to eliminate superconductivity in the films.Jcat 76 K decreased from 25 000 A/cm2in the unirradiated sample to 2000 A/cm2after a fluence of 2.1×1013O/cm2. A room‐temperature anneal caused bothTcand the normal‐state resistivity to recover slightly after low‐fluence irradiations.