Background: The rate of chronic opioid use after cardiac surgery is high compared with other surgical specialties; however evidence regarding optimal prescribing is limited. The purpose of this study was to evaluate patterns of opioid consumption after cardiac surgery to guide prescribing practices. Methods: Consecutive patients undergoing sternotomy-based cardiac operations were considered for enrollment. Patients with opioid use within 3 months of surgery and those discharged to a nonhome facility were excluded. A patient diary and researcher-directed pill count was used to track pain and opioid use for 10 days after discharge. Results: One hundred four patients were included in the final analysis. Of the 63 patients discharged with an opioid, 22 (34.9%) used none and 12 (19.0%) used fewer than half of the pills prescribed. Overall, pain and opioid consumption decreased significantly throughout the discharge period (P <.001). In those who used opioids after discharge, median total consumption was 64 morphine milligram equivalents (interquartile range, 38-128), or the equivalent of 9 oxycodone 5-mg tablets. Patients who used opioids were younger (60.9 vs 70.0, P <.001), but there were no differences based on sex, history of substance use, smoking, or procedure. After risk adjustment the mean pain score ≥ 3 on the day of discharge was predictive of opioid use (odds ratio, 2.9; 95% confidence interval, 1.8-4.8; P <.001). Most patients (88.5%) were satisfied or very satisfied with pain management. Conclusions: Fewer than half of all patients used opioids after discharge in this study. These data support the need for the development of prescription recommendations after cardiac surgery.