Errors in Abstract and Text. In the Original Investigation by Roizenblatt et al titled “A Double-blind, Placebo-Controlled, Crossover Study of Sildenafil in Obstructive Sleep Apnea,” published in the September 18 issue of the ARCHIVES (2006;166:1763-1767), errors appeared in both the abstract and the text. In the “Methods” section of the abstract, the first word should have been “Thirteen” because 13, rather than 14, participants were included in the study; therefore, the “Results” section of the abstract should have read, “In comparison to placebo, a single 50-mg dose of sildenafil significantly increased the percentage of total sleep time with an arterial oxygen saturation of less than 90% (mean ± SD, 15.6% ± 9.6% vs 7.9% ± 3.3%, P<.01), without a difference in the nadir of oxygen desaturation. The mean arterial oxygen saturation also decreased (92.1%±1.9% vs 93.8% ± 1.3%, P=.03), and the desaturation index increased (30.3 ± 14.5 events per hour vs 18.5 ± 9.1 events per hour, P<.001). There was an increase in apnea-hypopnea index (48.1 ± 20.8 events per hour vs 32.3 ± 11.3 events per hour, P<.001), involving mostly obstructive events.” Also, the first sentence of the “Results” section of the text on page 1764 should have read, “As mentioned, after screening for cardiovascular and pulmonary disease or metabolic syndrome, only 13 of the 49 middle-aged men with severe OSA recruited for this study were selected (age, 53.1±9.8 years; body mass index, 26.7 ± 1.9).”