This study examined evoked response potentials (ERPs) to angry and neutral faces in 15 individuals with post-traumatic stress disorder (PTSD) and 15 age and sex-matched controls over temporal (T5,T6) and occipital (O1,O2) regions. Twenty faces with an angry expression were alternated with 20 faces with a neutral emotional expression. There were significantly larger early negative (N110) and late negative (N650) ERP components in controls to the angry compared to the neutral faces. The PTSD group did not display ERP differences between angry and neutral faces, and the amplitude of their negative waveforms were reduced relative to controls. These findings may reflect adaptive, rapid responding to potential threat in the controls, and a reduced capacity to discriminate between non-threat and generalized threat stimuli in PTSD.