This study investigated characteristics and variables associated with self-harm in patients in a psychiatric unit which accepted children aged 7-13 years. It sought specifically to determine the role of emotion regulation as a motivation for self-harm in children. The study involved hypothesis driven examination of case files from 80 in patients admitted between 2003-8 to the Child and Family Therapy Unit (CFTU) at the Royal Children’s Hospital, Brisbane, Australia. Inpatients were selected, independent of the researchers, based on scores for HoNOSCA Item 3: ‘Non-accidental self-injury’. Forty inpatients (‘self-harm group’) had been scored on admission by inpatient staff as 2 (mild problem but definitely present), 3 (moderately severe problem) and 4 (severe to very severe problem). Forty inpatients (the ‘No self-harm comparison group’) had been scored 0 (No problem) or 1 (Minor problem requiring no action). Most common methods were ‘cutting’ and ‘head-banging’. The self-harm group differed from the comparison group in terms of family-related factors such as living situation, and psychological functioning as measured by the Strengths and Difficulties Questionnaire (SDQ), total HoNOSCA scores, and a history of sexual abuse. Our hypothesis that children engage in self-harm to regulate their emotions was not supported. Explanations for the findings and implications for research, intervention and prevention are discussed.