The urban poor living a life of uncertainty and insecurity throughout the year, are compelled to adopt various survival strategies to meet the challenges of their daily existence. In our study, micro-level data gathered through field surveys conducted in Kolkata’s slums was used to develop an understanding of the multi-dimensional nature of poverty and the diversification of these livelihood strategies. It was observed that a major chunk of workers earn their livelihood through physical labour, although income levels differ across and within occupational categories. As households move up the economic ladder, the contribution to the total household income from domestic work and scavenging declines, while that from self-employment rises. The transport sector workers, however, defy such trends. Using probit regression, we examined the determinants of the choice of modes of employment by poor urban workers, and note that more educated workers heading large households and having their fathers engaged in self-employment made them more likely to be involved in forms of self-employment activities.