Primary care is a cornerstone of the U.S. child health system (Donaldson et al. 1996; Starfield 1998). While many definitions of primary care exist, there is a general consensus on at least four defining features to assess its performance: accessibility, continuity, comprehensiveness, and coordination (Starfield 1994). As the receipt of high quality primary care has been associated with improved health (e.g., lower morbidity and mortality) (Lurie et al. 1984; Franks and Fiscella 1988; Shi 1994; Chande and Kinnane 1996; Safran et al. 1998; Shi, Green, and Kazakova 2004), and lower health care costs (e.g., fewer hospitalizations and emergency visits) (Bindman et al. 1995; Blumenthal, Mort, and Edwards 1995; Forrest and Starfield 1996; Gill, Mainous, and Nsereko 2000; Christakis et al. 2001), it is a major focus of national aims to reduce disparities and improve child health outcomes (U.S. Department of Health and Human Services 2000). Despite its value, many children do not receive adequate primary care. Children in lower socioeconomic status (SES) families, the uninsured, and racial/ethnic minorities frequently have been reported to have poorer primary care experiences (Newacheck, Hughes, and Stoddard 1996; Ortega et al. 2000; Weech-Maldonado et al. 2001; Newacheck et al. 1998, 2002; Stevens and Shi 2002; Elster et al. 2003; Lurie et al. 2003; Seid, Stevens, and Varni 2003), and poorer health status (Montgomery, Kiely, and Pappas 1996; Brooks-Gunn and Duncan 1997; Lave et al. 1998; Goodman 1999; Flores et al. 1999; DiLiberti 2000; Holl et al. 2000; Bradley and Corwyn 2002; Wood et al. 2002; Fox et al. 2003; Newacheck et al. 2003). Given weakening state budgets across the nation, access to needed high quality primary care for these vulnerable children may be further compromised. Public health insurance and public health care delivery programs that provide essential primary care services to many children—and account for nearly one-third of the state budget in California—continue to teeter on the edge of the political chopping block, threatening the viability of these safety-net programs for children. Children in noncitizen families and those residing in rural areas (both prominent issues in California) are at even higher risk for poor primary care, as even safety-net delivery programs often overlook rural areas and noncitizens are generally excluded from state insurance programs (Inkelas et al. 2003). Children served by public programs are considered vulnerable because they frequently have multiple risk factors for poor health status and poor primary care (e.g., living in poverty and not having health insurance) (Aday 2001). Previous research on child health and health care disparities has primarily focused on identifying and delineating the individual effects of these risk factors. Such an approach is important to identify new relationships and derive causal mechanisms, and forms the basis of most of our understanding of child health disparities. Since risk factors often cluster together, however, e.g., parents who did not graduate high school (one risk), are more likely to work in low-wage jobs (a second risk) and not have health insurance (a third risk)—understanding how multiple risk factors combine to influence primary care is an important next step. One alternate approach builds on existing knowledge to describe individuals according to risk profiles that allow the reader to explore the influence of multiple risk factors in a more explicit and interpretable way (Shi and Stevens 2005). Previous studies that have used this risk profile technique have shown that vulnerability to poor health is not defined by a single demographic, social, behavioral, or financial risk. In many instances, poor health outcomes have been associated with the multiplicity of risk factors a child or adolescent has. Sameroff et al. (1987) have shown an additive association between the number of family risk factors (e.g., minority status, low maternal education, poor maternal mental health) and child social-emotional health and IQ. Furstenberg et al. (1999) has demonstrated that family factors (e.g., single-parenting), community risks (e.g., neighborhood safety), and peer influences (e.g., antisocial peers) combine to influence adolescent social health and performance in school. More recent studies by Starfield, Robertson, and Riley have also combined both parent education and employment status to reveal an association between higher social class and child health status (Starfield, Robertson, and Riley 2002; Starfield et al. 2002). Single risk factor focused assessments have some limitations in informing interventions, since they may tend to lead to more narrowly focused approaches to resolving disparities rather than more integrated, multisector interventions to improving child health. Understanding how risk factors combine to influence child health status and primary care and how such risk profiles are distributed in the population may provide better guidance in where to intervene to achieve the greatest results. Few studies assess how combinations of risk factors are distributed in the child population, and those few studies mentioned do not explicitly examine the combined influences of risk factors on disparities in child health status or primary care (Shi and Stevens 2005). Understanding vulnerability in terms of multiple, overlapping risk factors for inadequate primary care is an important next step. Policy makers and those charged with monitoring access to care for vulnerable children might benefit from using this multiple risk factor approach to identify children who have the greatest health care needs and are least likely to obtain care. Even though more complex statistical techniques are available to describe the combined influences of multiple risk factors (i.e., multiple interaction terms), they create challenges in interpretation for policymakers. A more straightforward assessment of child vulnerability using risk profiles, particularly when combined with detailed analyses of the various common combinations, may help to better guide the allocation of resources, interventions, or outreach to improve the delivery of primary care at the population, health plan, or individual clinic level. This study uses data on children and adolescents ages 0–19 from the 2001 California Health Interview Survey (CHIS) to construct a vulnerability risk profile for each child based on five factors: child race/ethnicity, household poverty status, parent education, health insurance coverage, and primary language. The prevalence of these profiles is presented overall and then according to two family factors (immigration status and geographic residence) that have been the focus of recent policy debates about access to care in California, including new legislation to cover all children regardless of immigration status through expansions of county-based health insurance programs into geographic areas with high rates of uninsurance. The profiles are used to examine disparities in child health status and three aspects of primary care (i.e., access, continuity, and comprehensiveness of care). To provide the most policy-relevant results, the relationship of risk profiles with primary care access is examined by child health status (i.e., health need).