Introduction: Suicide is very common among people with mental disorders. In addition, suicide mortality rates are stable in this group, while they are decreasing in the general population. Methods: The vital statuses of adult inpatients admitted to French psychiatry departments in 2008–2009 were researched in death databases on 31 December 2013. Suicide probability was calculated using a Kaplan–Meier analysis, and standardized mortality ratios (SMRs) were calculated in relation to the population of the study area. Results: Among the 13,979 patients included in the study, (7416 men and 6563 women; mean age 43.6 ± 14.6 years), 1454 died in total, among whom 286 died by suicide an average of 4.9 years after the date of their enrolment. The cumulative probability of suicide was 0.8% at 1 year, 1.3% at 2 years and 2.5% at 6 years. The SMR value, which was 1492 for the whole group of patients and was twice as high in women (2494) as in men (1220), decreased with age (from 2078 in patients aged 18–34 years to 1278 in patients aged 75 years or more). Discussion: Our study confirms that suicide mortality is higher in inpatients admitted to French psychiatry units than in the general population and advocates specific prevention programmes for this group. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature