Persistent overactive bladder and urgency urinary incontinence after sling surgery (pubovaginal sling or midurethral sling) in women with mixed urinary incontinence (MUI) is devastating to patients and frustrating to surgeons who perform anti-incontinence surgery. To better predict the outcomes of sling surgery in women with MUI, preoperative parameters need to be examined to accurately predict postsurgical outcomes. In this review article, we will explore recent literature exploring possible preoperative predictors of persistent overactive bladder and urgency urinary incontinence after sling surgery in women with MUI.