It is estimated that half of unintended pregnancies could be averted if emergency contraception (EC) were easily accessible and used. To evaluate the effect of direct access to EC through pharmacies and advance provision on reproductive health outcomes. A randomized, single-blind, controlled trial (July 2001-June 2003) of 2117 women, ages 15 to 24 years, attending 4 California clinics providing family planning services, who were not desiring pregnancy, using long-term hormonal contraception or requesting EC. Participants were assigned to 1 of the following groups: (1) pharmacy access to EC; (2) advance provision of 3 packs of levonorgestrel EC; or (3) clinic access (control). Primary outcomes were use of EC, pregnancies, and sexually transmitted infections (STIs) assessed at 6 months; secondary outcomes were changes in contraceptive and condom use and sexual behavior. Women in the pharmacy access group were no more likely to use EC (24.2%) than controls (21.0%) (P = .25). Women in the advance provision group (37.4%) were almost twice as likely to use EC than controls (21.0%) (P<.001) even though the frequency of unprotected intercourse was similar (39.8% vs 41.0%, respectively, P = .46). Only half (46.7%) of study participants who had unprotected intercourse used EC over the study period. Eight percent of participants became pregnant and 12% acquired an STI; compared with controls, women in the pharmacy access and advance provision groups did not experience a significant reduction in pregnancy rate (pharmacy access group: adjusted odds ratio [OR], 0.98; 95% confidence interval [CI], 0.58-1.64; P = .93; advance provision group: OR, 1.10; 95% CI, 0.66-1.84, P = .71) or increase in STIs (pharmacy access group: adjusted OR, 1.08, 95% CI, 0.71-1.63, P = .73; advance provision group: OR, 0.94, 95% CI, 0.62-1.44, P = .79). There were no differences in patterns of contraceptive or condom use or sexual behaviors by study group. While removing the requirement to go through pharmacists or clinics to obtain EC increases use, the public health impact may be negligible because of high rates of unprotected intercourse and relative underutilization of the method. Given that there is clear evidence that neither pharmacy access nor advance provision compromises contraceptive or sexual behavior, it seems unreasonable to restrict access to EC to clinics.