We estimated deaths amenable to high-quality health care globally and then modeled the macroeconomic impact in low- and middle-income countries using two macroeconomic perspectives: a value-of-lost-output approach to project gross domestic product (GDP) losses annually for the period 2015-30, and a value-of-lost-welfare approach to estimate the present value of total economic welfare losses in 2015. We estimated that eight million amenable deaths occurred in 2015, 96 percent of them in low- and middle-income countries. The value of lost output resulted in a projected cumulative loss of $11.2 trillion in these countries during 2015-30, with a potential economic output loss of up to 2.6 percent of GDP in low-income countries by 2030, compared to 0.9 percent in upper-middle-income countries. The value-of-lost-welfare approach estimated welfare losses of $6.0 trillion in 2015. Inadequate access to high-quality health care results in significant mortality and imposes a macroeconomic burden that is inequitably distributed, with the largest relative burden falling on low-income countries. Given that these deaths are unnecessary and the projected GDP losses are avoidable, there is a strong ethical and economic case for promoting high-quality health care as an essential component of universal health coverage.