Undergraduate volunteers from the Psychology participant pool ( N = 86, age M = 22.7, SD = 4.8 yr.; 72 of 86 were female) took two tests, a commercially available integrity test (the Personnel Selection Inventory) and the NEO-Five Factor Inventory. Later in the study, each participant was given an opportunity to report dishonestly the amount of time spent in the laboratory and thus to receive more extracredit points than earned. An observer recorded participants' actual times in the laboratory to provide an accurate assessment of participants' honesty. Analysis indicated that the Personnel Selection Inventory did not predict whether the participant was honest or dishonest in reporting time spent. Conscientiousness as measured by the NEO-Five Factor Inventory, however, not only predicted behavior, but did so significantly better than did the Personnel Selection Inventory. The study provides new information about the value of integrity tests by comparing integrity and personality tests in the simultaneous prediction of a specific criterion.