Delays in treatment are common and pose a significant threat to patient safety. This study evaluated nearly 7000 patients who experienced a cardiac arrest due to “shockable” rhythms, and discovered an alarming rate of delays to defibrillation. Noted in 30% of cases, delays were associated with noncardiac admitting diagnoses, care received in an unmonitored unit, and occurrence after hours or on the weekend. Patients who received delays in treatment were ultimately found to have lower rates of survival after the in-hospital arrest. The study findings raise numerous opportunities for systems improvement, including better training of code teams with simulation methods, and particular attention to such training in teaching institutions. A study in the pediatric literature demonstrated similar delays around resuscitative efforts.