Indium tin oxide (ITO) films have been prepared by DC magnetron sputtering. In order to improve the utilization efficiency of the target and reduce the cost of the film deposition processes, the powder target was used instead of the conventional ceramic target. As-deposited films were annealed at temperatures between $200^{circ}C$ and $500^{circ}C$ for 30 min in air. Also, the film was annealed in various atmospheres such as air, $O_2,;H_2,;N_2$, and vacuum at $400^{circ}C$C for 30 min. Effects of the heat treatment conditions on structural, electrical, and optical properties of ITO films were investigated. The annealing temperature of $400^{circ}C$ and atmospheres of $H_2$ and $N_2$ seem to be the most suitable conditions for post processing.