Background There is a dearth of information on suicidal thoughts and acts or other acts of deliberate self‐harm by offenders under community supervision. Aims The objective of this study is to estimate lifetime and one month prevalence of deliberate self‐harm and to determine ongoing risk among offenders in the community under probation supervision. Methods One hundred and seventy‐three randomly selected offenders under supervision by the probation service in one county in England were screened for mental illness. All 88 screened cases and a one‐in‐five sample of non‐cases were interviewed according to the Mini International Neuropsychiatric Inventory Module‐B. False negatives (n = 17) were used to weight calculations and estimate prevalence for the whole group. Results A third of the interviewed sample (n = 56) had a lifetime history of suicide attempts, and 9 (5%) had self‐harmed in the month prior to interview. Lifetime suicide history was associated with suicidal ideation and deliberate self‐harm in the prior month. Conclusions and implications Our adjusted findings indicate that 25‐40% of offenders serving all or part of their sentence in the community have a lifetime history of self‐harm, which is similar to the rate among prisoners, and are at very much higher risk of further such acts or completed suicide than the general population. At a time of change in delivery of probation services the implications are thatrates of suicide and other forms of deliberate self‐harm should be continually assessed in all probation areas, particularly with reference to service changes;the relationship between deliberate acts of self‐harm, suicidal ideation and completion of suicide should be investigated prospectively in larger studies;probation services are likely to need mental health expertise to manage these risks Copyright © 2014 John Wiley & Sons, Ltd.