If you miss your company's open enrollment period for health insurance benefits, you may be out of luck unless you have recently experienced a significant, life-changing event that would trigger a special enrollment period. A special enrollment period could be triggered if you are covered on someone else's plan and lose that coverage. For example, if you are covered on your spouse's plan, but your spouse loses her job or you become divorced, this would trigger a special enrollment period that would allow you to enroll in your company's health plan right away. Additionally, if you marry, have a child, or adopt a child, you could enroll your dependents right away in a special enrollment period.
If nothing has happened to trigger a special enrollment period, you will most likely have to wait until the next open enrollment period to sign up for health benefits. While you still cannot be denied coverage due to your health status, as a late enrollee, you could be subject to a longer pre-existing condition exclusion period.