Purpose Sickness absence is an important indicator of the health status of workers. socio-demographic and occupational characteristics generally, are among the main factors associated with sick leave, as well as being a problem for the management of human resources. The aim of this paper was analyse the prevalence and factors associated with sickness absence to workers at a university hospital.

Methods Cross-sectional study in a service call to the server responsible for approval of sick leave of a Brazilian Federal University, among which the permanent workers who carry out their activities at the university hospital. The population consisted of all the professionals who worked in the hospital in 2013, which were absent from work and deliver the medical certification to justify their absence, in the occupational health service.

Results 597 medical licenses were granted to 223 servers, which resulted in 11.623 days of absence, averaging absence of 52 days per server licensed. Prevalence of sick leave was 70.5 episodes for every 100 servers with higher frequency of episodes of long-term sick leave (51.7%). Mental disorders accounted for the highest number of days lost 5.688, and the highest average duration of days absent per server licensed 84 days (± 78).

Multivariate analysis showed significant association between permits for health treatment and the female variables (OR 2.2, 95% CI: 1.3 to 3.6) and professional category nursing assistants (OR 3.1, 95% CI: 1.7 to 7.3). The quantity of allowances and the total number of days of absence, represent the magnitude of the situation found in the period of the study.

Conclusion Female gender and the professional category of nursing assistants are associated with higher absence rates at work. The data reflect the illness profile in the study hospital and cause receivership need to develop actions to reduce the levels found.