The PROMIS-29 v2.0 profile assesses pain intensity using a single 0-10 numeric rating item and seven health domains (physical function, fatigue, pain interference, depressive symptoms, anxiety, ability to participate in social roles and activities, and sleep disturbance) using four items per domain. This paper describes the development of physical and mental health summary scores for the PROMIS-29 v2.0.We conducted factor analyses of PROMIS-29 scales on data collected from two internet panels (n = 3000 and 2000).Confirmatory factor analyses provided support for a physical health factor defined by physical function, pain (interference and intensity), and ability to participate in social roles and activities, and a mental health factor defined primarily by emotional distress (anxiety and depressive symptoms). Reliabilities for these two summary scores were 0.98 (physical health) and 0.97 (mental health). Correlations of the PROMIS-29 v2.0 physical and mental health summary scores with chronic conditions and other health-related quality of life measures were consistent with a priori hypotheses.This study develops and provides preliminary evidence supporting the reliability and validity of PROMIS-29 v2.0 physical and mental health summary scores that can be used in future studies to assess impacts of health care interventions and track changes in health over time. Further evaluation of these and alternative summary measures is recommended.