For the U.S. and for Norway it has been established that men and women working in the same occupation for the same employer receive more or less the same pay. So-called within-job wage discrimination is hence not a driving force for the gender wage gap. We report a comparative and comprehensive empirical study of wage differences between men and women in the same detailed occupation within the same establishment for a European economy, Sweden. We report three striking findings. The first is that within-job wage differences are relatively small. When one compares men and women who work in the same occupation and establishment: Women on average earn 1.4% less per hour than men among blue-collar workers, while 5.0% less among white-collar workers. The second finding is that among white-collar workers it is occupational segregation which really accounts for the existing wage differences and that establishment segregation accounts for less, whereas among blue-collar workers the two types of segregation are about equally important. The third finding is that even the within-occupation gaps are relatively small, less than 5% and 7% among blue- and white-collar workers respectively. We conducted these analyses for the period 1970-1990 and the results are stable over time.