The case notes of 295 suicides (98.3% of the total) in prisons in England and Wales between 1972 and 1987 were studied. This period has witnessed an increase in the suicide rate far in excess of the rate of rise in the prison population. The most common method of suicide was by hanging, usually at night. There was a frequent past history of psychiatric treatment and self-injury. People charged or convicted of violent or sexual offences were over-represented, as were those serving life sentences. There was an association between suicide and both guilt for the offence and being charged or convicted of a homicide offence. Some suicides occurred many years after reception into prison. Routine enquiry about previous suicide attempts must be implemented, along with better, ongoing, active communication between staff and inmates.