This study examines levels of traumatic stress reactions among youth attending school in the second year after the 1994 Rwandan genocide. From August to December 1995, the survey team visited 22 schools throughout Rwanda. The survey (n = 942; youth aged 8 to 19 years) assessed exposure to wartime violence and symptoms of posttraumatic stress disorder (PTSD), as outlined in the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM–IV; American Psychiatric Association, 2000). Mean symptom levels and the proportion of respondents meeting DSM–IV PTSD symptom criteria (“probable PTSD”) were examined for evidence of systematic decline over time. Multivariate analyses controlled for major confounders and the complex survey design. Overall, traumatic stress reactions increased among youth interviewed at successively later time points. For example, in the first third of the survey period, the “probable PTSD” rate was 48%; in the second, 54%; and in the third, 58%. The rise was confined to females. Among females, the adjusted odds of having “probable PTSD” in the last third of the study period was 2.71 (95% CI [1.66, 4.43]) fold higher than in the first. These results suggest that in planning health services in postconflict settings, humanitarian agencies should be alert to the possibility that traumatic stress reactions among youth may not decline with passage of time. Despite limitations in design, to date, this report represents the only formal structured evaluation of the mental health of youth living in the community, in the very early aftermath of catastrophic violence.