An Institute of Medicine (IOM) report recommends development of a standardized, core set of indicators focused on priority health outcomes (Institute of Medicine. Committee on Public Health Strategies to Improve Health, 2011). The IOM also recommends changes in the processes, tools and approaches for gathering information on health outcomes. Several groups have been working to identify and test concepts of health and function that are meaningful across countries and cultures (Taskforce on Health Status, 2005). The Patient-Reported Outcomes Measurement Information System (PROMIS; www.nihpromis.org) adopted the World Health Organization framework to define three components of health: physical, mental and social (World Health Organization, 1946) (see http://www.nihpromis.org/measures/domainframework). This is congruent with the biopsychosocial approach adopted by many health psychologists (Engel, 1977, 1980). Measures of social health will play a key role in applications that use ecologic (or determinants of health) models that emphasize how patients’ environments influence their health (Institute of Medicine, 2003; Institute of Medicine. Committee on Public Health Strategies to Improve Health, 2011; Whitehead, 1995). This is of particular significance given that social health has historically been a relatively neglected domain due to the lack of measures for clinical populations, as well as disagreement about how best to define and measure it (Hahn, Cella, Bode, & Hanrahan, 2010). Social health measures that can be used across chronic illness populations are essential given findings that individuals who receive appropriate social support and are integrated within their communities experience better health outcomes than those who experience social isolation (Broadhead et al., 1983; Bruhn & Philips, 1984; McDowell, 2006; Mitchell, Billings, & Moos, 1982). At the broadest level, social health includes health outcomes as well as social processes that play an important role in influencing other health outcomes, e.g., mediating or moderating the effects of stress on physical health and illness. In some contexts (e.g., family or group therapy), processes such as social support can be outcomes of interventions. The PROMIS domain framework for Social Health (v2.0) includes two primary sub-components: Social Function and Social Relationships (McDowell, 2006) (see supplemental Figure 1). As described in detail elsewhere, PROMIS initially developed two sets of Social Function items (Ability to Participate and Satisfaction with Participation, v1.0) and tested them in a general population English-speaking sample (Hahn et al., 2010). Results showed that some item refinement was necessary, and that clinical samples should be included in future testing to evaluate our conceptual models and produce measures for use across chronic illnesses. Additionally, development of Social Relationships items was needed as well as Spanish language versions in order to address the rising need for assessment tools appropriate for Latinos/Hispanics, who constitute the fastest growing group among minority populations that are often underserved in health care settings and excluded from research studies (Garber & Arnold, 2006; Yancey, Ortega, & Kumanyika, 2006). Establishing cultural equivalence across populations is particularly important for social health, which inherently includes cultural norms against which social roles and support are assessed (McDowell, 2006). The aim of the work we present here was to develop psychometrically sound, culturally relevant and linguistically equivalent English and Spanish language self-report measures of adult social health guided by a comprehensive conceptual model and applicable across chronic illnesses. This manuscript describes the work of the PROMIS Social Health Workgroup to refine and expand the PROMIS Social Health measures (v2.0), test the items with large samples of English- and Spanish-speaking adults, and derive item response theory (IRT)-based item banks (sets of calibrated items). These calibrated item banks are comprised of numerous items that allow for computerized adaptive testing (CAT) and development of multiple short forms of varying length that provide accurate measurement with low response burden (Cella, Gershon, Lai, & Choi, 2007).