While numerous factors contributing to racial/ethnic health disparities have been identified, the clustering and interaction of these factors as a syndemic or trajectory has not been well-studied (Starfield in Soc Sci Med 64:1355-1362, 2007; Singer in Soc Sci Med 39(7):931-948, 1994). More importantly, for immigrant/refugee populations, the interaction of contributing factors is not documented adequately enough to provide a solid framework for planning, implementation and evaluation of interventions aimed at reducing disparities. In this paper, the authors draw from the literatures on health disparities and immigrant/refugee health, as well as direct program and research experience, to propose an approach for assessment of the diachronic interaction of ecological factors (a trajectory, or "diachronic ecology") contributing to health disparities among immigrant/refugee populations. It is our hope that this approach will contribute to the important effort to collect data supporting the development of interventions and policies that effectively address the dynamic processes through which health disparities are created, maintained, and changed.