In humans, one component of the acoustic startle response is a reflex eye blink that can be elicited with a sudden burst of noise of at least 90 dB, making the eye blink a common marker of the startle response because it can be easily recorded. An exaggerated startle response is a clinical feature often reported by patients with PTSD and is one of the hyperarousal or Criteria D symptoms of the DSM-IV diagnostic criteria for PTSD. The current testing of this alleged link between an exaggerated startle response and PTSD involved 28 adolescent girls with diagnosed PTSD and 23 healthy control girls. Both samples were exposed to bursts of white noise of 104 dB presented to both ears through headphones. The two groups of girls were compared on baseline startle responses as well as prepulse inhibition, a 1,000-Hz prestimulation tone presented continuously for 2,000 milliseconds before the startle stimulus. At baseline and under neutral testing conditions, the magnitude of the startle response (eye blink measurement) did not differ significantly between the two groups; and neither were there significant differences between the groups in the degree of prepulse inhibition or facilitation. These findings contrast with some studies (Butler et al., 1990; Orr et al., 1995; Shalev et al., 1992) but not all studies (Grillon et al., 1996, and Orr et al., 1997b) conducted with male combat veterans with PTSD. The findings of the current study, however, are similar to those in one other published study of acoustic startle response in traumatized women (Metzger et al., 1999). Possible explanations for the findings of the current study are discussed, along with clinical implications. 2 tables and 34 references