The migration of rural laborers into cities for employment has been one of the main driving forces of China's economic growth over the past three decades. Based on a dataset collected by the Ministry of Agriculture of China from 2003 to 2007, this paper examines the impact of health on the earnings of migrant workers engaging in physically-intensive work requiring good health. Our findings indicate that a poor health status not only weakens the incentive of rural laborers to participate in the migrant labor force but also significantly reduces their earnings. A migrant worker in poor health only earns 67 percent of what a healthy worker makes. Among all the human capital characteristics and family economic factors, health status is the most influential on earnings for less educated workers. Labor productivity has a greater impact on earnings than the annual number of days that a person works. Ongoing health-care reforms aimed at the improvement of the health-care services available to rural laborers are urged to help reduce poverty in rural China.