We have examined endurance of Spindt-type field emitter arrays (FEAs) against oxygen ambient. In this study,: the endurance of four different emitter materials, Ni, Pt,Au, and Mo was investigated. The electron emission characteristics of FEAs with 1 to 1600 tips were measured in ultrahigh vacuum (UHV) and in oxygen ambient. For all the FEAs, the emission current decreased with an increase in oxygen pressure. Some of the emitters were destructed during the emission test in oxygen ambient. The detailed analyses of the emission characteristics were performed by calculating the noise power and observing the emission pattern on the phosphor screen. The noise power increased with an increase in oxygen pressure. Emission pattern on the phosphor screen showed enlarged emission area,as compared with the pattern obtained in UHV. The present results indicated that even the Pt emitters were affected by the ambient oxygen. The,elimination of oxygen is the essential subject for the development of field emission display.