Observations in psychiatric in-patient settings are used to reduce suicide, self-harm, violence and absconding risk. The study aims were to describe the characteristics of in-patients who died by suicide under observation and examine their service-related antecedents. A national consecutive case series in England and Wales (2006-2012) was examined. There were 113 suicides by in-patients under observation, an average of 16 per year. Most were under intermittent observation. Five deaths occurred while patients were under constant observation. Patient deaths were linked with the use of less experienced staff or staff unfamiliar with the patient, deviation from procedures and absconding. We identified key elements of observation that could improve safety, including only using experienced and skilled staff for the intervention and using observation levels determined by clinical need not resources.