The State of Texas began enforcement of the Woman's Right to Know (WRTK) Act on January 1, 2004. The law requires that all abortions at or after 16 weeks' gestation be performed in an ambulatory surgical center (ASC). In the month the law went into effect, not one of Texas's 54 nonhospital abortion providers met the requirements of a surgical center. The effect was immediate and dramatic. The number of abortions performed in Texas at or after 16 weeks' gestation dropped 88 percent, from 3,642 in 2003 to 446 in 2004, while the number of residents who left the state for a late abortion almost quadrupled. By 2006, abortions at or after 16 weeks' gestation in a nonhospital setting were available in four major cities in Texas (down from nine in 2003), and the abortion rate at or after 16 weeks' gestation remained 50 percent below its pre-Act level. Regulation of abortion providers that require new facilities or costly renovations could have profound effects on the market for second-trimester abortions. (Contains 6 figures, 5 tables, and 29 footnotes.)