We evaluated the validity of the Perinatal Posttraumatic Stress Disorder Questionnaire (PPQ) as a measure of posttraumatic stress symptomatology. Mothers of high-risk infants (N = 91) and healthy, full-term infants (N = 51) answered the PPQ and two other convergent measures of posttraumatic stress disorder symptoms, the Impact of Event Scale (IES) and the Penn Inventory (PI). The Need for Cognition Scale (NCS) was used as a divergent measure. Correlations among the convergent measures were significantly greater than the correlation between the PPQ and NCS. High-risk mothers also scored higher than normal mothers on the PPQ and IES. The results support the validity of the PPQ.