In this study, we propose a group-based trajectory analysis to examine why and how people fall into and out of poverty despite spiralling public expenditure on anti-poverty policies. By analyzing the poverty experiences of 1,001 low-income households between 1999 and 2008 in Korea, we identify five groups based on their poverty trajectories: exiting, declining, slowly rising, rapidly rising and chronic. Household members in each group demonstrate heterogeneous labour market experiences, educational levels and demographic factors. The exiting group has a high proportion of full-time workers, high school graduates, and younger and male-headed households, whereas the chronic group has more part-time workers, high school dropouts, and older and female-headed households. Among the declining, slowly rising and rapidly rising groups, educational background, age and sex are factors that differentiate the poverty dynamics of household members. Lastly, a number of social policies for helping low-income households to leave and stay out of poverty are proposed.