Zr-N films have been deposited by direct current reactive magnetron sputtering using a plasma emission monitoring (PEM) control system, where a signal proportional to the light emitted by the sputtered Zr in the plasma created by the electrical discharge was used to control the admission of the reactive nitrogen into the system. The Zr line set point for PEM control, phi, was used as a parameter; as the partial pressure of nitrogen rises the Zr line emission falls due to target poisoning, The influence of the nitrogen partial pressure on the Zr-N film structure, reflectivity, resistivity, and internal stress was investigated. The effect of ion flux during film deposition on the film properties was also investigated, The Zr-N films deposited at the Zr line set point phi=60%-70% revealed the minimum resistivity and goldlike reflectivity spectra. These films showed a ZrN single phase. The internal stress of the films showed a maximum at phi=60%-70%, which corresponds to the condition for depositing minimum resistivity films. The external magnetic field scarcely affected the optical and the electrical properties of the deposited Zr-N films. The internal stress of the films deposited at the lower phi (higher nitrogen partial pressure) was only dependent on the ion flux.