OBJECTIVE To examine the impact of specific training for accident and emergency (A&E) staff on the quality of psychosocial assessment of deliberate self harm patients. METHODS A non-randomised intervention study that compared the psychosocial assessment of deliberate self harm patients before and after a one hour teaching session for the A&E departments nursing and junior medical staff. Adequacy of psychosocial assessment was judged by examining A&E case notes. The records of the hospital's parasuicide team were examined to assess administrative changes. Staff attitude to and knowledge of deliberate self harm were also measured before and after the intervention. RESULTS 45 of 52 nurses and all 15 junior medical staff attended the teaching session. Sixteen (13%) of 125 sets of records before and 58 (46%) of 127 sets of records after the intervention were judged to be adequate. In the postintervention period, notes were more likely to be judged adequate when a proforma was used as part of the assessment (52 of 66 with a proforma and six of 61 without a proforma, chi2 = 60, p < 0.01). Following the intervention, communication between A&E staff and the hospitals parasuicide team improved. CONCLUSIONS An intervention that provides teaching to A&E staff can lead to improvements in the quality of psychosocial assessment of patients with deliberate self harm.