When Is Medicare Secondary Payer? 
If you are still working and your employer allows you to stay on the group coverage and you are 65 and enroll into Medicare then your group insurance is primary and medicare is secondary . What if you have medicare and medicaid-medicare pays first . What if you have retired and you have coverage through the group plan-Medicare pays first . What if you are disabled but your spouse is still working and you are covered by the grou plan-if fewer than 100 employees - Medicare pays first-if more than 100 employees-the group plan pays first . What if you have End Stage Renal Disease-during the first 30 months the group plan pays first and medicare secondary ; afgter 30 months Medicare pays first and the group plan is secondary . If you have End Stage Renal Disease AND Cobra - first 30 months Cobra is primary and medicare is seondary and after first 30 months Medicare is primary and Cobra is secondary . If your case is not shown just ask if your case is preimary or secondary on the internet 