TESIS PARA OPTAR AL GRADO DE MAGÍSTER EN ECONOMÍA / Sleeping is probably the most frequent consumption and investment activity of humans, but it has been relatively understudied in economics. In this paper we use a time use global dataset and test competing theories to explain the differences in sleeping time between the rich and the poor around the world. We find that high income full-time workers tend to sleep less than those of low-income. Average estimates show a 10-20 minute lower sleep for the top quartile vis-a-vis poorer quartile of full-time workers. This stylized fact is robust to several covariates using panel data regressions, holding both across countries and, most importantly, within the countries in our sample. Furthermore, the observed negative covariation of income and sleep among workers, is consistent with a potential substitution effect with several leisure activities, like commute, surfing on the internet and outside socializing activities, all of which are also positively (and significantly) correlated with household income.