In the present work, we have explored the growth of ZnO nanorods from a zinc acetate precursor by a thermal decomposition process at 300 °C. Our key observation indicates that a lower heating rate favors the formation of ZnO nanorods while faster heating rates favor the formation of a mixture of ZnO nanorods and nanoparticles. Further, the fabrication of films using dispersions of these nanostructures has been carried out by a low cost spin coating route, which leads to formation of vertically oriented nanorods. The field emission studies of the ZnO film consisting of pure ZnO nanorods show a field enhancement factor of 18 990 while ZnO films containing a mixture of rods and particles show a field enhancement factor in the range of 8571–8829. The field enhancement factor of ZnO nanorods is significantly higher than the previous reports on ZnO nanorods grown by complex physical routes. We have shown a one-step process which results in the formation of high quality ZnO nanorods which is very important for making high end optical and electronic devices.