The association between births that are small for gestational age and outdoor airborne polycyclic organic matter (POM) was examined in New Jersey, a highly urban state. This pilot study utilizes a cross-sectional investigation combining maternal and pregnancy outcome information from birth certificates with air toxics data from the U.S. Environmental Protection Agency Cumulative Exposure Project and census data at the census tract level. The exposure categories were based on tertiles of modeled average POM concentrations for each census tract in New Jersey. High POM exposure was positively associated with delivery of "small for gestational age" (SGA) births. After adjustment for potential individual-level confounding factors, the odds ratios for term, preterm, and all SGA were 1.22 (1.16-1.27), 1.26 (1.07-1.49), and 1.22 (1.17-1.27), respectively, for the highest exposure tertile in the urban population of the state (89% of the state's birth population). For group-level variables, the corresponding ORs were 1.12 (1.07-1.18), 1.23 (1.02-1.47), and 1.13 (1.07-1.18). The results of this study suggest that residential exposure to airborne polycyclic organic matter (POM) is associated with increased prevalence of "small for gestational age" births among urban population. Cross-sectional investigations combining air dispersion models with routinely collected population-based health and census data could be a useful approach for identifying the hazardous air pollutants of greatest public health concern.