Human resources for health (HRH) will have to be strengthened if universal health coverage (UHC) is to be achieved. Existing health workforce benchmarks focus exclusively on the density of physicians, nurses and midwives and were developed with the objective of attaining relatively high coverage of skilled birth attendance and other essential health services of relevance to the health Millennium Development Goals (MDGs). However, the attainment of UHC will depend not only on the availability of adequate numbers of health workers, but also on the distribution, quality and performance of the available health workforce. In addition, as noncommunicable diseases grow in relative importance, the inputs required from health workers are changing. New, broader health-workforce benchmarks - and a corresponding monitoring framework - therefore need to be developed and included in the agenda for UHC to catalyse attention and investment in this critical area of health systems. The new benchmarks need to reflect the more diverse composition of the health workforce and the participation of community health workers and mid-level health workers, and they must capture the multifaceted nature and complexities of HRH development, including equity in accessibility, sex composition and quality.