Hollow hematite (alpha-Fe2O3) microspheres with an average diameter of 3-4 mu m and a shell thickness of approximate 150 nm was synthesized by a simple hydrothermal route using FeCl3 center dot 6H(2)O solution and acetic acid without using any templates. The hollow microspheres were composed of alpha-Fe2O3 nanoparticles with the diameter range from 20 to 40 nm. The effects of reaction parameters such as reaction time, temperature, concentration of FeCl3 center dot 6H(2)O solution, and initial pH on the morphology of the final products were investigated. A possible formation mechanism of hollow alpha-Fe2O3 microspheres was also proposed, where the acetic acid played a role of etching in the formation of hollow structure.