OMS reports describe an increase of levels of sickness leaves (SL) at work in all industrialized countries in last decades. Aims of this study are to assess incidence of SL from work in a sample of women public employees and to identify significant factors, among individual, behavioural, familiar, occupational and work strain related. The survey took place between April 1992 and December 1998. After the baseline examination, a two years follow-up was conducted, to detect any SL longer than one day. N. 8123 female employees of the Municipality of Milan were enrolled, undergoing a baseline health examination. They belong to the following municipality sectors (SM): kindergarten, register office, clerks and police. The overall response rate was 76% (3698 females and 2448 males). The present analysis was restricted to female only, who showed almost double incidence of SL than men. Interpolation of logistic models allowed to identify the following predictive independent factors: physical activity in leisure time, work length and social support at work, for incidence of short SL; physical activity at work, hypertension and smoking habit for intermediate SL; and perceived work strain and number of familiar contacts for long SL.