The SAT® has changed in several ways over the eight decades that it has been administered to college-bound high school students, including changes in both content and format (for a review, see Lawrence, Rigol, Van Essen, and Jackson, 2002). The original test administered in 1926 contained both verbal and mathematics content and was highly speeded, with a total time limit of 97 minutes. Subsequent modifications and additions to the SAT have resulted in testing times ranging from 120 to 180 minutes. Prior to the most recent revision in 2005, the SAT involved 180 minutes (3 hours) of testing across a total session of about 3½ hours (to accommodate instructions, short breaks, and administration time). In 2005, the most recent significant change in both content and format has been the introduction of an essay section and some modifications in the other sections (e.g., the elimination of verbal analogy items). The addition of the essay section has resulted in an SAT test that involves 225 minutes (3 hours, 45 minutes) of total test time spread over a period of about 4½ hours (that includes instructions, short breaks, and administration time). Examinees arrive at the place of testing before 8 a.m. to check in, and do not complete the SAT session until approximately 12:30 p.m. The high-stakes nature of the test, coupled with the increased total testing time, has resulted in speculation from a variety of sources, especially in the popular press (e.g., FairTest, 2006; FOXNews.com, 2006; Hildebrand, 2007; Lewin, 2005; MacDonald, 2005) that (a) performance on the SAT is negatively affected by the additional testing time; (b) examinee fatigue increases as a function of the increased total testing time; and, by implication, (c) that examinee fatigue is an influential factor in performance on the SAT. The current study was designed to examine performance effects and fatigue effects associated with different total SAT testing times. In addition, we examined personality, motivation, and other determinants of individual differences in examinee fatigue before, during, and after testing.