In this paper, I explore Helena Maria Viramontes’s Under the Feet of Jesus published in 1995, in terms of what I call “postcolonial environmental injustice.” That is, I demonstrate that through the hard life of Estrella’s family, Viramontes shows how Mexican workers have been oppressed in American society. They have been exploited as cheap, “illegal” laborers without legal protection; They have been threatened by dangerous working conditions. In addition, I explore this work with postcolonial approach, on the basis of the historical background that through the Mexican War in 1846 and the Treaty of Guadalupe Hidalgo in 1848 Mexicans lost their lands and property rights; Since then, Mexican laborers have been exploited as “illegal” migrant workers. In short, I demonstrate that in Under the Feet of Jesus, Viramontes shows the postcolonial environmental injustice that has been done on Mexican migrant workers. By shedding a spotlight on these invisible migrant workers who are racially, socioeconomically, and environmentally underprivileged and oppressed, Viramontes ultimately critiques American society.