Importance: Access to health insurance that is not contingent on employment allows non-elderly adults to retire early, especially if they have a serious health condition. Similar workers who rely on employment for health insurance may choose to continue working, potentially harming their health in retirement.  Objective: To examine the influence of retiree and employment-contingent insurance on retirement behavior and health of workers diagnosed with cancer.  Design: This longitudinal cohort study conducted analyses using the Health and Retirement Study, 2000-2018.  Setting: The Health and Retirement Study is population-based for adults aged 50 and older.  Participants: We selected respondents and spouses who reported a new cancer diagnosis (n=354) and a matched, non-cancer sample (n=1,770 respondents), restricting both samples to those employed and working at 10+ hours, and younger than age 63.  Exposure: Employment contingent health insurance and retiree health insurance.  Main Outcome(s) and Measure(s): Employment, weekly hours worked, and health outcomes assessed at the diagnosis interview and 2 years post diagnosis.  Results: Women in the cancer sample with retiree insurance were 21.0 percentage points less likely to work (95% CI  –38.5 to –3.5; p<0.05). Employed women with cancer but no health insurance increased weekly hours worked by 32% relative to similar non-cancer controls. Men with a new cancer diagnosis and without health insurance were also less likely to work (17.6 percentage points; 95% CI –3.5 to –0.03; p<0.05). The absence of employment-contingent insurance was associated with hospital stays in the past two years for women (44% among workers). Among women who stopped working, those without employment-contingent or retire insurance were in fair or poor health (82%) and 73% reported a hospital stay in the past two years. Most men (92%) without employment-contingent insurance reported fair or poor health. None of the men with employment-contingent insurance reported fair or poor health and only 25% of men with both employment-contingent insurance and retiree benefits reported fair or poor health.  Conclusions and Relevance:  Policies that support health insurance outside of employment may allow ill workers to retire early and those who must continue working, benefits like paid sick leave could be critical to their well-being.