This paper uses national survey data to measure the degree of gender discrimination in the UK labour market in the 1990s and compares this to results from earlier decades. It concludes that discrimination is still an important cause of the gender pay gap: women's pay would increase by about 10 per cent if they were rewarded in the labour market on the same basis as men. But this unequal treatment has declined since the 1980s, when equivalent figures were nearer 20 per cent. This decline in discrimination has been a more important cause of the reduction in gender pay differentials than women's relative increase in human capital. Female part-timers experience a greater degree of discrimination than female full-timers: their pay would increase by about 15 per cent if their human capital attributes were remunerated in the same way as men's. As there is such a large difference between male and female part-timers, however, in their human capital endowments, discrimination explains proportionately less of the pay gap between male and female part-timers than it does between male and female full-timers.