Disclosed herein are cracking catalysts useful in the thermo-catalytic cracking (TCC)--formerly called selective deep catalytic cracking (SDCC)--of petroleum naphthas, gas oils and other heavy hydrocarbon distillates to selectively produce light olefins, said catalyst comprising mesoporous mixed oxides modified by the presence of inorganic compounds containing chemical elements selected from phosphorus, sulfur, chlorine and mixtures thereof, said catalyst being supported on yttria stabilized zirconium oxide and/or aluminum oxide. Preferably, the catalyst will have the the following formula: (a) MoO.sub.3 and/or WO.sub.3; (b) La.sub.2O.sub.3; (c) CeO.sub.2; (d) P, S or Cl; (e) ZrO.sub.2; (f) Y.sub.2O.sub.3. Also preferably, the catalyst will be combined with a material selected from an acidic crystalline (modified or not) zeolite, an acidic silica molecular sieve and an acidic alumina. Also disclosed are methods of making said cracking catalysts. The cracking catalysts can be used in both mono- and dual reactor configurations. Furthermore, the catalysts of the present invention have a sufficiently high thermal (and steam atmosphere) resistance, enabling them to be used at significantly higher temperatures.