District costs for teachers' health insurance are, on average, higher then employer costs for private-sector professionals. How much of this is attributable to collective bargaining? This article examines the question using data from the National Compensation Survey (NCS) of the Bureau of Labor Statistics (BLS) and the state of Wisconsin. In addition, the impact of collective bargaining on employer costs is decomposed into the impact on total premiums and the employer's share of those premiums.