Purpose: The purpose of this paper is to examine the impacts of rural-urban migration on agricultural (labor) productivity in China. Design/methodology/approach: This paper closely follows the framework of Rozelle et al. (1999), Taylor et al. (2003) and Atamanov and Van den Berg (2012)—new economics of labor migration—to demonstrate the heterogeneous effects of migration on agricultural productivity, using simultaneous equations extended by an interaction term of off-farm income and household wealth. Findings: The results empirically verify two key theoretical predictions: the loss of labor available for agricultural activities decreases rice yield per worker per day, and the off-farm income that may relax liquidity constraints has a positive offsetting effect, which becomes weaker with increasing household wealth. The final calculation based on these two contradictory influences indicates that the lost-labor effect dominates across all levels of household wealth, resulting in a negative net impact of rural-urban migration on agricultural productivity. The key results are shown to hold for land productivity as well. Originality/value: To the best of the author's knowledge, it is the first paper to examine the impacts of rural-urban migration on labor productivity and the heterogeneity across households with different levels of wealth. A major policy issue facing national leaders is whether the massive and ongoing outflow of labor will be a threat to China's rural development and its food security in the future. This paper provides insightful ideas in a different way.