The effectiveness of a locally developed trauma-focused cognitive behavioural therapy (TF-CBT) program for maltreated children with post-traumatic stress disorder (PTSD) was examined across different therapists in a child protection clinic setting. An earlier phase of the research piloting the program had provided promising results. This second phase involved two studies evaluating the completed TF-CBT manual delivered by (a) the developer and (b) other therapists. A single-case multiple-baseline design was used to demonstrate the controlling effects of the treatment on PTSD symptoms and childcoping. Eight 9–13-year-old abused children with PTSD were treated. Positive outcomes support the effectiveness of the TF-CBT program delivered by both the developer and other therapists. The study design and methodology were robust enough to confirm empirically the clinically beneficial effects and potential for this new program. It was also apparent, however, from study limitations, including missing data for some patients, that there are a number of challenges in carrying out such research in a busy child protection service setting with multiply-abused patients. This paper considers implications and ways forward for engaging in empirically supported practice as well as future development and research.