This paper reviews our recent progress on the synthesis and transport studies of novel transition metal oxide nanowires, including YBa₂Cu₃O_6.66, Fe₃O₄, La_0.67Sr_0.33MnO₃ and PbZr_0.58Ti_0.42O₃. Key to our success is the growth of standing single-crystalline MgO nanowires, which worked as excellent templates for epitaxial deposition of the desired transition metal oxides and led to high-quality core–shell nanowires. Transport studies have been conducted on both Fe₃O₄ and La_0.67Sr_0.33MnO₃ core–shell nanowires. Devices based on individual Fe₃O₄ nanowires exhibited room-temperature magnetoresistance of 1.2% under a magnetic field of B = 1.8 T, as a result of tunnelling of spin-polarized electrons across anti-phase boundaries. In addition, devices made of La_0.67Sr_0.33MnO₃ nanowires showed a remarkable metal–insulator transition at 325 K, accompanied by room-temperature colossal magnetoresistance (CMR) ~10% under a 1 T magnetic field. More interestingly, shape-induced magnetoresistance was also observed at room temperature with the La_0.67Sr_0.33MnO₃ nanowires. Our technique could enable various in-depth studies such as phase transition in nanoscale oxides and may pave the way for novel applications of these fascinating materials.