The first bill being considered by a Missouri House committee this year would prohibit the payment of union fees from being a condition of employment.
The legislation, known as "right to work," is getting a hearing in the House Workplace Development and Workplace Safety Committee.
It is a top priority for Republican House Speaker Tim Jones, of Eureka. He led a rally of about 100 activists in support of the bill before the legislative session opened last week.
While the proposal is at the top of the House agenda, Senate leaders haven't been as optimistic about it passing this year.
The measure is sponsored by Republican Rep. Eric Burlison, of Springfield.