This paper examines the connection between immigration status, English language proficiency, and educational achievement as determinants of poverty among Mexico-born migrants in Chicago, U.S. The theoretical framework of the study uses Human Capital Theory and the analysis is based on a multistage cluster probabilistic sample (2005-2006) of Mexican migrants obtained in Cook County which includes the City of Chicago. Analyses of contingency tables and logistic regression models show that the most relevant connections occur between poverty and immigration status as well as between poverty and English language proficiency. Thus, Mexican immigrants with citizenship status, work permits, or residency permits (“green cards”) and Mexican immigrants with high English language proficiency have a lower probability to be below the poverty threshold than their counterparts. The analysis of the sample’s educational achievement in Mexico shows that these immigrants tend to have low levels of education and that the problems associatedwith school dropout among Mexican migrants extends below high school. Similarly, the educational achievement obtained in the U.S. is significantly low among the individuals in the sample. These results point to the plight of the large levels of undocumented workers with low English proficiency and suggest the existence of structural problems that impede significant returns to human capital investments on Mexican education in the U.S. labor market.