Error in infertility statistics and incorrect reference. The article “Evaluation and Treatment of Endometriosis” (January 15, 2013, p. 107) contained errors in the abstract (p. 107), in the text under the “Epidemiology” header (p. 108), and in reference 14 (p. 112). In the second sentence of the abstract, the percentages of women with pelvic pain and infertility diagnosed with endometriosis were inadvertently switched, and the percentage for women with infertility was incorrect. The sentence should have read: “It [endometriosis] is more common in women with pelvic pain or infertility (70 to 90 percent and 21 to 40 percent, respectively).” In the fourth sentence under the “Epidemiology” header, the percentage of women with infertility also diagnosed with endometriosis was incorrect. The sentence should have read, “Endometriosis is diagnosed in 21 to 40 percent of women with infertility…” Also, reference 14 in the reference list was incorrect, and should have been: Ozawa Y, Murakami T, Terada Y, et al. Management of the pain associated with endometriosis: an update of the painful problems. Tohoku J Exp Med. 2006;210(3):175–188. The online version of the article has been corrected.