This study prospectively examined the relationships among cognitive factors and severity of Posttraumatic stress disorder (PTSD) symptoms in female victims of sexual violence. Thirty-eight victims of sexual violence recruited from Center for Women Victims of Sexual and Domestic Violence at Ajou University Hospital. Cognitive factors and PTSD symptom were assessed within 4 months of sexual violence and 25 victims were followed-up 1 month after initial assessment. Repeated-measured ANOVA revealed that PTSD incidence and severity decreased over the month (F [1, 21]=6.61). Particularly, avoidant symptoms might decrease earlier than other PTSD symptoms (F [1, 21]=5.92). This study also showed the significant relationship between early negative trauma-related thoughts and subsequent PTSD severity. Shame and guilt proneness had significant cross-sectional correlations with PTSD severity, but did not show associations when depression severity is controlled. Our results suggest that avoidant symptoms might decrease earlier than other PTSD symptoms during the acute phase and that cognitive appraisals concerning the dangerousness of the world seem to play an important role in the maintenance of PTSD (r=0.499, P<0.05).