The cathodoluminescent characteristics of phosphor screens excited by cold electrons from field emitter arrays can be influenced by the resistivity of the phosphor screen. The resistivity of ZnGa2O4:Mn phosphor screens was determined experimentally and the correlation between the screen resistivity and the luminance was obtained. Addition of WO3 to ZnGa2O4:Mn phosphor was one way of controlling the resistivity, and subsequently the luminance. In field emission displays (FEDs), the resistivity of the phosphor screen gives rise to a voltage drop on the anode side and modifies the emission characteristics of emitters, which leads to a negative effect on the luminance. The luminance has been generally expressed as L = eta IanodeVanode. But With the resistivity of the phosphor screen taken into consideration, it should be expressed as L = eta IanodeVphosphor. For either reason, the resistivity of the phosphor needs to be held as low as possible to get the maximum luminance out of FED. Experiments show that the resistivity of ZnGa2O4 :Mn phosphor is typically 10(10) Omega cm.