The goal of this study is to identify primary drivers of audit budget inaccuracy. Our results show a positive association between using the budget for evaluative purposes and favorable (or less unfavorable) budget variances. In addition, despite the fact that our sample is comprised of continuing audit engagements, weak client controls and relatively uncooperative clients have the greatest impact on unfavorable budget variances. Our results suggest audit budgets insufficiently accommodate client-controlled factors. © 2006 Elsevier Ltd. All rights reserved.