I examine whether the availability of health coverage through the spouse's health plan influences a married woman's decision to become self-employed. The Tax Reform Act of 1986 (TRA86) introduced a tax subsidy for the self-employed to purchase their own health insurance. I test whether this “natural” experiment induced more women without spousal health insurance coverage to select into self-employment. The most conservative difference-in-difference estimates based on an analysis of employed women indicate that the incidence of self-employment among single women rose by 10% in the post-TRA86 period, while a multinomial specification based on a sample of both employed and nonemployed women suggests that the increase was about 13%. (JEL J0, J3, I1)