Wellmark Blue Cross Blue Shield is a mutual insurance in the United States with more than two million members in Iowa and South Dakota. It is the dominant health insurance in Iowa. It is an independent licensee of the Blue Cross Blue Shield Association. Founded in 1939, Wellmark offers dental and health insurance as well as life insurance. It began participating in the health care exchange for 2017.

In 1939, 'Hospital Service Incorporated of Iowa' (later known as Blue Cross of Iowa) began business in Des Moines, Iowa. That same year, 'Associated Hospital Services Incorporated' (later known as Blue Cross of Western Iowa and South Dakota) was established in Sioux City, Iowa. In 1945, Iowa Medical Service (later known as Blue Shield of Iowa) was formed. In 1948, Associated Hospital Services began doing business in South Dakota and marketing activities as Blue Cross. In 1956 'South Dakota Medical Service' began doing business in South Dakota as South Dakota Blue Shield. In 1986, Blue Cross and Blue Shield of Iowa purchased Benefit Administrators of America, Inc., a third-party administrator, which was the plans' first for-profit venture. Benefit Administrators of America was renamed Wellmark Administrators, Inc. in 1997.

In 1989, Blue Cross of Iowa, Blue Shield of Iowa and Blue Cross of Western Iowa and South Dakota merged to form 'IASD Health Services Corporation'. In 1991, IASD Health Services Corporation became a mutual insurance. In 1994, Blue Cross Blue Shield (BCBS) allowed its licensees to be for-profit corporations, and the joint service agreement of Blue Cross of South Dakota and South Dakota Blue Shield expired, putting the two plans in competition with one another.

In 1996, Blue Shield of South Dakota merged into IASD to form a single company. Blue Cross of South Dakota and South Dakota Blue Shield merged into 'South Dakota Health Services Company' doing business as Blue Cross Blue Shield of South Dakota. In 1997, the companies were branded as Wellmark Blue Cross and Blue Shield of Iowa and Wellmark Blue Cross and Blue Shield of South Dakota.

Wellmark is headquartered in downtown Des Moines and Sioux Falls. It has 1707 employees in Iowa and 171 in South Dakota. It consists of Wellmark Blue Cross and Blue Shield of Iowa, Wellmark of South Dakota, Inc. (doing business as Wellmark Blue Cross and Blue Shield of South Dakota) and Wellmark Health Plan of Iowa, Inc. The Wellmark Foundation is a private foundation to support health improvement initiatives in Iowa and South Dakota.

Wellmark insures almost 1.8 million Iowans and more than 300,000 South Dakotans. It is Iowa's largest and dominant insurer but has not participated in the government's health care exchange for two years in a row. During its open enrollment period from October 1, 2013 to March 31, 2014 more than 41,000 people in Iowa and South Dakota enrolled in 24,000 "Affordable Care Act-compliant health plans" by Wellmark. Cliff Gold, former Wellmark employee, then chief operating officer of Iowa's CoOportunity, said that "they have denied consistently, that they [...] push bad risk into the exchanges."

As of 2016^[update] the Board of Directors consists of 11 members, namely Thomas M. Cink, Melanie C. Dreher, John D. Forsyth, Daryl K. Henze, William C. (Curt) Hunter, Paul E. Larson, Angeline M. Lavin, Terrence J. Mulligan, Dave Neil, Timothy J. Theriault, Terri M. Vaughan. The CEO is Cory Harris.

Wellmark's credit rating from Standard and Poor's was "A+" (Strong).