Medical Mutual of Ohio Medical Mutual of Ohio Search | Advanced Search | New Members | Coupons and Discounts | All Categories Finance & Insurance >> Insurance Carriers Medical Mutual of Ohio Currently serving 1.6 million members. Medical Mutual, an Ohio-base mutual health insurance company with regional offices in Powell, has offered individual and group health plans to businesses like yours for more than 75 years. Member Since: 2010 Need to update your categories or expand your listing? Or want to learn how your business can become a part of the Chamber? Contact us at membership@columbus.org for assistance.