This paper explores whether the agglomeration of human capital leads to social employment advantages in urban labor markets of Colombia. It compares employment opportunities in urban areas where the level of education differs while controlling for plausible confounders using census data for 1993 and 2005. Results show that employment opportunities are higher on average in skilled urban areas than in low-skilled urban areas. Recent literature has offered at least three explanations for this positive effect: human capital externalities, production complementarities, and consumption spillovers. To distinguish between them, I analyze the effect of an increase on the college share on the employment rate for different education groups. An increase in the supply of college graduates only affects the employment rates of primary and high-school dropouts. Human capital externalities and production complementarities explain the spatial employment differences in Colombia.