Research has shown that the job access of the poor has been declining because of two major reasons: the spatial distribution of employment and housing, and socioeconomic restructuring. This paper aims to untangle the effects of the two factors on poor job seekers’ access to jobs in the Chicago metropolitan area from 1990 to 2010. Using census tracts as the unit of analysis, this research examines the effects of these two factors on the growth and distribution of poor job seekers and their matching jobs, as well as the consequential changes in job demand, supply and job access across the study area. Results show that spatial changes have increased job accessibility for the poor while socioeconomic transformation has adversely affected it.