In 2016, the Centers for Disease Control and Prevention (CDC) issued opioid prescribing guidelines that recommended limiting the duration of therapy for acute pain. Research has found that the guidelines have changed opioid prescribing in the emergency department, but less is known about the impact on postoperative opioid prescribing. This study examined the effect of opioid prescribing duration limits in Massachusetts and Connecticut on postoperative prescribing. Dosing duration limits resulted in decreases in postoperative prescription size and days supplied in Massachusetts but not in Connecticut.