Comprehensiveness of primary care (the extent to which the clinician, as part of the primary care team, recognizes and meets the majority of each patient’s physical and mental health care needs) is an important element of primary care, but seems to be declining in the U.S. This is concerning, because more comprehensive primary care is associated with greater equity and efficiency in health care, improved continuity, less care fragmentation and better health outcomes. Without measurement and support for its improvement, comprehensiveness may further decline as other measured aspects of primary care (e.g. access, coordination) improve. To track, support and improve comprehensiveness, it is useful to have valid and reliable ways to measure it. This paper discusses challenges to measuring comprehensiveness for a primary care team’s patient panel, presents survey and claims-based measures of comprehensiveness, and provides suggestions for future research.