The study of occupational segregation is shown to be related to that of income inequality, the gender ratio in each occupation playing the role of individual income. Measures of the dispersion, skewness, kurtosis, and concentration of the distribution of this gender ratio are suggested, and an empirical illustration based on Swiss data for the period 1950–1980 is given. Finally bootstrap techniques are used to check the impact of classification errors and aggregation on the measurement of occupational segregation.