How important is short-term labor migration within developing countries? Scholars have long conceived dual developing economies, linked by costly permanent migration from the rural sector to seek urban employment. However, these theoretical models have largely overlooked short-term migration. Similarly, existing data oer limited opportunities to study the details of households use short-term migration to combine these livelihoods. The primary contribution of this paper is to analyze new data about 705 households from 70 villages in rural Rajasthan, Gujarat, and Madhya Pradesh. Data collection emphasized detailed migration histories, and found that short-term migration was common and frequent. Over half of the adults in our sample, belonging to 80 percent of households, left the village for work at least once between summer 2009 and summer 2010. The median trip lasted 30 days; very few exceeded four months. Such migration is sharply seasonal, and rarely becomes a permanent move. Within the villages we study, less educated people are more likely to migrate than more educated people and people from poorer households are more likely to migrate than people from richer households. Short-term migration allows non-agricultural work to be a large component of the livelihoods of otherwise agricultural households. It creates channels for economic spillovers among rural and urban growth, poverty, and policies.