BACKGROUND: The Kingdom of Saudi Arabia (KSA), as part of its 2030 National Transformation Program, set a goal of transforming the healthcare sector to increase access to, and improve the quality and efficiency of, health services. To assist with the workforce planning component, we projected the needed number of physicians and nurses into 2030. We developed a new needs-based methodology since previous global benchmarks of health worker concentration may not apply to the KSA. METHODS: We constructed an epidemiologic "needs-based" model that takes into account the health needs of the KSA population, cost-effective treatment service delivery models, and worker productivity. This model relied heavily on up-to-date epidemiologic and workforce surveys in the KSA. We used demographic population projections to estimate the number of nurses and physicians needed to provide this core set of services into 2030. We also assessed several alternative scenarios and policy decisions related to scaling, task-shifting, and enhanced public health campaigns. RESULTS: When projected to 2030, the baseline needs-based estimate is approximately 75,000 workers (5788 physicians and 69,399 nurses). This workforce equates to 2.05 physicians and nurses per 1000 population. Alternative models based on different scenarios and policy decisions indicate that the actual needs for physicians and nurses may range from 1.64 to 3.05 per 1000 population in 2030. CONCLUSIONS: Based on our projections, the KSA will not face a needs-based health worker shortage in 2030. However, alternative model projections raise important policy and planning issues regarding various strategies the KSA may pursue in improving quality and efficiency of the existing workforce. More broadly, where country-level data are available, our needs-based strategy can serve as a useful step-by-step workforce planning tool to complement more economic demand-based workforce projections.