Opinions about the purpose and effectiveness of test preparation seminars vary, but it is clear that preparation for standardized tests is here to stay. The literature suggests that students do benefit from preparation for standardized tests. The effect of test preparation seminars on standardized achievement tests was studied for 30 of 100 high school juniors from Queen of Peace High School (Burbank, Illinois), who participated in a 10-hour preparation program for the American College Test (ACT). All subjects were female and most were white. The pretest consisted of retired copies of the ACT, and the posttest was the current ACT. As hypothesized, there was a gain in posttest scores. These gains were consistent with others found in the literature. Findings suggest that students may be wise to take some form of test preparation seminar before taking standardized achievement tests like college entrance examinations. The literature further suggests that preparation for aptitude tests should differ from that for achievement tests. (SLD)