Due to limited social protection, individuals in South Korea tend to purchase private health insurance which covers income loss as well as medical expenditures from health shock. This paper examines how the effects of cancer diagnoses on medical utilization, earnings, and household income vary with insurance status, using panel event study approach and data from Korea Health Panel from 2009 to 2018. We find that the increase in medical utilization following a cancer diagnosis is larger and more persistent for the insured, with smaller heterogeneous effects by insurance status for lower-income households. In addition, the insured experience larger decreases in earnings relative to the uninsured and temporary increases in household income with insurance payments but not among the uninsured.