Previous research suggests that both men's and women's level of sickness absence may be systematically related to the gender composition of their workplace as well as of their occupational category. The number of studies is, however, low and the composition of the occupational category has often been used as a proxy for the composition of the workplace. This paper employs a large data set broadly representative of the employed population of Norway. The data make it possible to take workplace and occupation simultaneously into account. Thus, the relationship between the gender composition of the workplace and sickness absence is estimated with detailed control for differences between occupational categories. Likewise, the importance of the gender composition of the occupation is assessed with control for between workplace variation. Men's sickness absence turns out to be largely unrelated to the gender composition of the workplace. For women the level of sickness absence tends to be higher in female-dominated workplaces, but the relationship is weak. These findings provide evidence against theories suggesting that the minority sex in the workplace faces special problems and is therefore more absent. They are to some extent consistent with the idea that female-dominated workplaces develop norms that are more tolerant towards sickness absence. The relationship of sickness absence to the gender composition of the occupational category is similar to the U-shaped pattern found in several previous studies (highest sickness absence both in strongly male-dominated and strongly female-dominated occupations), but again the relationship is weak.