ImportanceChanges in postsurgical opioid prescribing practices may help reduce chronic opioid use in surgical patients.ObjectiveTo investigate whether postsurgical acute pain across different surgical subspecialties can be managed effectively after hospital discharge with an opioid supply of 3 or fewer days and whether this reduction in prescribed opioids is associated with reduced new, persistent opioid use.Design, Setting, and ParticipantsIn this prospective cohort study with a case-control design, a restrictive opioid prescription protocol (ROPP) specifying an opioid supply of 3 or fewer days after discharge from surgery along with standardized patient education was implemented across all surgical services at a tertiary-care comprehensive cancer center. Participants were all patients who underwent surgery from August 1, 2018, to July 31, 2019.Main Outcomes and MeasuresMain outcomes were the rate of compliance with the ROPP in each surgical service, the mean number of prescription days and refill requests, type of opioid prescribed, and rate of conversion to chronic opioid use determined via a state-run opioid prescription program. Postsurgical complications were also measured.ResultsA total of 4068 patients (mean [SD] age, 61.0 [13.8] years; 2528 women [62.1%]) were included, with 2017 in the pre-ROPP group (August 1, 2018, to January 31, 2019) and 2051 in the post-ROPP group (February 1, 2019, to July 31, 2019). The rate of compliance with the protocol was 95%. After implementation of the ROPP, mean opioid prescription days decreased from a mean (SD) of 3.9 (4.5) days in the pre-ROPP group to 1.9 (3.6) days in the post-ROPP group (P P P = .02). There was no statistically significant difference in surgical complications. The conversion rate to chronic opioid use decreased following ROPP implementation among both opioid-naive patients with cancer (11.3% [143 of 1267] to 4.5% [118 of 2645]; P P = .02).Conclusions and RelevanceIn this cohort study, prescribing an opioid supply of 3 or fewer days to surgical patients after hospital discharge was feasible for most patients, led to a significant decrease in the number of opioids prescribed after surgery, and was associated with a significantly decreased conversion to long-term opioid use without concomitant increases in refill requests or significant compromises in surgical recovery.