Resistivity and transport critical current density have been measured as a function of temperature for patterned YBa2Cu3O7−&dgr;and Bi2Sr2CaCu2O8+&dgr;superconducting thin films on single‐crystal (100)‐oriented MgO substrates. These granular superconducting films were prepared by the metallo‐organic decomposition method. Transition temperaturesTc(&rgr;=0) are around 72 K for YBa2Cu3O7and 82 K for Bi2Sr2CaCu2O8films, both 1 &mgr;m in thickness. Critical current densities approaching 105A/cm2have been measured in the Bi2Sr2CaCu2O8films at low temperatures. The critical current densities in YBa2Cu3O7films are about 40 times lower than those in the Bi2Sr2CaCu2O8films. It was found that nearTcthe critical current density in both films is proportional to (Tc−T)2, in agreement with a superconductor–normal‐metal– superconductor model developed by DeGennes [P. G. De Gennes, Rev. Mod. Phys.36, 225 (1964)]. The reason for the much higher current density in the Bi2Sr2CaCu2O8film is believed to be due to the stronger coupling between the superconducting grains.