In developing countries, when markets are incomplete migration can have multiple effects on agricultural production. In this paper, I use instrumental variables techniques to explore the effects of seasonal migration on agricultural production in rural Viet Nam during the 1990s. Instrumenting migration with network variables specific to Vietnam, I find that migration shapes agricultural production is several ways. Although there are no effects of migration on aggregate production, there is weak evidence that migrant households move somewhat out of rice production and into the production of other crops. Inputs used by migrant households also decrease relative to similar non-migrant households. In exploring the mechanisms by which these changes occur, I find evidence consistent with a move from labor intensive into land intensive crops, rather than productivity changes or a shift from using labor to capital as an input.