A probit model identifies characteristics influencing Idaho potato producer support or opposition to a state mandatory certified seed law. Economic self interest appears to be the most important influencer. Current users of certified seed and growers of certified seed are strong supporters. However, producer attitudes about the impact of seed-borne diseases and effectiveness of certified seed as a control mechanism also are important. Respondent characteristics (gross farm income, potato acreage, and geographic region of the state) seem to be less important influencers.