Use of dexmedetomidine or propofol rather than a benzodiazepine sedation strategy may improve ICU outcomes. We reviewed randomized trials comparing a benzodiazepine and nonbenzodiazepine regimen in mechanically ventilated adult ICU patients to determine if differences exist between these sedation strategies with respect to ICU length of stay, time on the ventilator, delirium prevalence, and short-term mortality. We searched CINAHL, MEDLINE, the Cochrane databases, and the American College of Critical Care Medicine's Pain, Agitation, Delirium Management Guidelines' literature database from 1996 to 2013. Citations were screened for randomized trials that enrolled critically ill, mechanically ventilated adults comparing an IV benzodiazepine-based to a nonbenzodiazepine-based sedative regimen and reported duration of ICU length of stay, duration of mechanical ventilation, delirium prevalence, and/or short-term mortality. Trial characteristics and results were abstracted in duplicate and independently, and the Cochrane risk of bias tool was used for quality assessment. We performed random effects model meta-analyses where possible. We included six trials enrolling 1,235 patients: midazolam versus dexmedetomidine (n = 3), lorazepam versus dexmedetomidine (n = 1), midazolam versus propofol (n = 1), and lorazepam versus propofol (n = 1). Compared to a benzodiazepine sedative strategy, a nonbenzodiazepine sedative strategy was associated with a shorter ICU length of stay (n = 6 studies; difference = 1.62 d; 95% CI, 0.68-2.55; I = 0%; p = 0.0007) and duration of mechanical ventilation (n = 4 studies; difference = 1.9 d; 95% CI, 1.70-2.09; I2 = 0%; p < 0.00001) but a similar prevalence of delirium (n = 2; risk ratio = 0.83; 95% CI, 0.61-1.11; I2 = 84%; p = 0.19) and short-term mortality rate (n = 4; risk ratio = 0.98; 95% CI, 0.76-1.27; I2 = 30%; p = 0.88). Current controlled data suggest that use of a dexmedetomidine- or propofol-based sedation regimen rather than a benzodiazepine-based sedation regimen in critically ill adults may reduce ICU length of stay and duration of mechanical ventilation. Larger controlled studies are needed to further define the impact of nonbenzodiazepine sedative regimens on delirium and short-term mortality.