The purpose of the current study was to examine the extent to which clients of a Stage 1 inpatient program for adult survivors of childhood trauma experienced improvements in their trauma-related symptoms during and following treatment. In addition, the study aimed to enhance our understanding of who benefited by examining trajectories of symptom change, and the extent to which pretreatment symptom severity differentiated the trajectory groups. We used a waitlist comparison methodology and a 6-month follow-up period to examine treatment outcome. We analyzed the data using linear mixed models and latent class growth modeling. Results indicated that the treatment group experienced significantly greater reduction in their trauma-related symptoms than the waitlist group, and this reduction was largely maintained 6-months following discharge. Examinations of group change trajectories indicated that there were 3 groups with distinct change patterns. Analyses examining pretreatment symptom severity in relation to change trajectories indicated that clients with a range of severities of trauma-related symptoms benefited from the program. Clients for whom the program was less effective in reducing trauma-related symptoms were those with severe anxiety and arousal symptoms at admission. The results support the efficacy of inpatient trauma treatment programs for adult survivors of childhood maltreatment, and suggest that modifications during and following treatment may assist a subset of clients in achieving similar gains.