Objectives The absenteeism in nursing staff has been the focus of many studies in different countries revealing a serious problematic in occupational health. The absenteeism according the lost workdays highlights the impact on patient care and the costs for the health institutions. Aimed analyse the sickness absenteeism in Brazilian nursing staff.

Methods Descriptive and quantitative study, accomplished after approval by the Ethics and Research Committee, was conducted in seven hospitals located in different Brazilian geographic regions, which constituted the intentional sample. The data were collected by Surveillance System of the Health Nursing Workers -SIMOSTE, on line system, validated and made available to record and capture data about the nursing health problems related to work. The data were sent by the settings, treated quantitatively and analysed by descriptive statistic.

Results Of the 890 occurrences captured by SIMOSTE in one year, there were 8081 days of sick leave, caused by mental disorders (30,75%), work-related musculoskeletal disorders (19,20%), and consequences of external causes (14,90%). The sick leaves, although work- related, were most recorder as medical licences (83,00%). This situation is extremely worrying, due to work overload that generate these absences to nursing staff, and the impact on quality of care provided to patients.

Conclusions The sick leave days are considered days lost. It means that in one year were 22 years of work. The mental disorders and diseases of the musculoskeletal system were the main causes of absence, confirming the pattern of sickness among nursing staff. This study allow us to disseminate advances in nursing research related to the health system and health services strategies.