This paper examines the evolution of gender segregation indexes by occupation in the urban labour markets of Colombia between 1986 and 2004 and presents a decomposition of their changes over time using a technique proposed by Deutsch et al. (2006). We find that a substantial proportion of the reduction in segregation indexes for this country is driven by changes in both, the employment structure of occupations and the increasing female labour participation observed over these years while changes in the gender composition of occupations have favoured mainly government employees and those with university education