For Mexican and Chinese immigrants it has been reported that foreign born children have a lower prevalence of asthma than U.S.-born children. Inner-city black populations have a high prevalence of asthma. However, despite growing populations of black immigrants, we are aware of no previous studies that have looked at the effect of nativity on their asthma prevalence. We report data collected from a convenience sample in the Dorchester neighborhood of Boston for black respondents. The survey was conducted by medical students and community residents using a community-based participatory research approach. For adult respondents (n = 290) there was a strong negative association between being born outside the United States and reporting asthma (OR = 0.39; p = 0.033) that was retained in our multivariate model. For children (n = 157, reported by their parents) there was also a strong association with being born outside the United States (p < 0.05 using chi(2) tabular analysis); however, there were no foreign-born children with asthma so an OR could not be calculated and this association could not be carried forward into multivariate analyses. For children, but not adults, there were also strong associations between asthma and environmental factors. These findings point to the need for further research into nativity and asthma in black U.S. populations. Future studies should seek to obtain a representative sample, gather more demographic data than we did and seek a larger sample of children. It makes sense to ask about nativity in asthma prevalence studies in order to distinguish these two apparently very different subpopulations.