Objective: The purposes of this study were to estimate suicide rates up to 4 years after a deliberate self-harm episode, to investigate time-period effects on the suicide rate over the follow-up period, and to examine potential sociodemographic and clinical predictors of suicide within this cohort. Method: This prospective cohort study included 7,968 deliberate self-harm attendees at the emergency departments of four hospital trusts in the neighboring cities of Manchester and Salford, in northwest England, between September 1,1997, and August 31, 2001. Suicide rates and standardized mortality ratios (SMRs) for the cohort were calculated. Potential risk factors were investigated by using Cox's proportional hazards models. Results: Sixty suicides occurred in the cohort during the follow-up period. An approximately 30-fold increase in risk of suicide, compared with the general population, was observed for the whole cohort. The SMR was substantially higher for female patients than for male patients. Suicide rates were highest within the first 6 months after the index self-harm episode. The independent predictors of subsequent suicide were avoiding discovery at the time of self-harm, not living with a close relative, previous psychiatric treatment, self-mutilation, alcohol misuse, and physical health problems. Conclusions: The results highlight the importance in a suicide prevention strategy of early intervention after an episode of self-harm. Treatment should include attention to physical illness, alcohol problems, and living circumstances. Self-harm appears to confer a particularly high risk of suicide in female patients.