Ten per cent of patients with schizophrenia commit suicide, but assessment of risk is difficult. Large case-control studies with a long follow-up period are needed. These should focus on patients from one age group to give clinicians the details required to identify those at highest risk.We present a case-control study of 63 patients who committed suicide and 63 controls from a consecutive admission series of patients with a diagnosis of schizophrenia. All patients were under the age of 30 at admission.Risk factors for suicide were male gender, chronic illness with frequent relapses (OR 6.0), frequent short hospitalisation, a negative attitude towards treatment (OR non-compliance 7.0), impulsive behaviour (OR acting out 6.4, OR involuntary commitment 17), parasuicide (OR suicide attempt 4.8, OR highly lethal suicide attempt 11), high pre-morbid IQ (OR 4.3), psychosis (OR 7.0) and depression (OR 36). However, early onset of a defect state (OR 6.3) and a daily activity (OR 4.2) were protective factors. Identified risk factors could help clinicians to target high-risk patients and form the basis for interventions aimed at reducing suicide.