Empirical and survey data collected from parties in states that require real estate licensees to have errors and omissions insurance is presented and analyzed. Satisfaction with the mandatory system was expressed by 68% of licensees and 89% of regulators. Variables that are significantly related to licensee satisfaction are identified. Perhaps most importantly, licensees who have operated under both voluntary and mandatory systems are more satisfied than those who have operated exclusively under a mandatory system. Motivations for mandating errors and omissions insurance include the desire to provide consumer and licensee protection, and affordable premiums for licensees. Recommendations for regulators considering mandating E&O insurance are presented.