Background: Drug product shortages, including injectable opioids, are common and have the potential to adversely affect patient care. Objective: To evaluate the impact of an injectable opioid shortage for hospitalized adult patients in the acute postoperative setting. Methods: A single-center, retrospective cohort study of noncritically ill hospitalized, postoperative patients requiring opioids for acute pain management was conducted. Patient cohorts were compared preshortage and postshortage for proportion of total intravenous (IV) opioids used, proportions of specific pain medications used, subjective pain scores, 30-day mortality, respiratory depression, need for opioid reversal, hospital length of stay, and opioid equivalent doses. Results: A total of 275 patients were included, 130 patients in the preshortage cohort and 145 in the postshortage cohort. The proportion of total IV opioid doses was lower in the postshortage cohort versus the preshortage cohort (16.6% vs 20.5%; P < 0.01). Specific medications used were significantly different between the cohorts. The proportion of severe pain scores was lower in the postshortage cohort versus the preshortage cohort (55.6% vs 58.5%; P = 0.04). No significant differences were seen in the overall proportion of nonopioid analgesic use, 30-day mortality, respiratory depression, need for emergent opioid reversal, hospital length of stay, or opioid equivalent doses between cohorts. Conclusion and Relevance: In hospitalized, postoperative adults, an injectable opioid shortage was associated with significant decreases in IV opioid use and severe pain scores but no significant differences in nonopioid analgesic use, safety outcomes, or opioid equivalent doses. These results may assist clinicians in developing strategies for injectable opioid shortages and generating hypotheses for future studies.