Introduction: Comprehensive data on the risk of hospital-acquired (HA) acute kidney injury (AKI) among adult users of opioid analgesics are lacking. This study aimed to systematically compare the risk of HA-AKI among the users of various opioid analgesics. Methods: This multicenter, retrospective real-world study analyzed 255265 adult hospitalized patients who received at least one prescription of opioid analgesic during the ?rst 30 days of hospitalization. Primary outcome was the time from the first opioid analgesic prescription to HA-AKI occurrence. 12 subtypes of opioid analgesics were analyzed, including 9 for treating moderate-to-severe pain and 3 for mild-to-moderate pain. We examined the association between the exposure to each subtype of opioid analgesic and the risk of HA-AKI using Cox proportional hazards models, using the most commonly used opioid analgesic as the reference group. Results: As compared to dezocine, the most commonly used opioid analgesic treating moderate-to-severe pain, exposure to morphine, but not the other 7 types of opioid analgesics, was associated with a significantly increased risk of HA-AKI (adjusted hazard ratio 1.56, 95% confidence interval [CI] 1.40-1.78). The association was consistent in stratified analyses and in a propensity-matched cohort. There were no significant differences in the risk of HA-AKI among the opioid analgesics users with mild-to-moderate pain after adjusting for confounders. Conclusion: The use of morphine was associated with an increased risk of HA-AKI in adult patients with moderate-to-severe pain. Opioid analgesics other than morphine should be chosen preferentially in adult patients with high risk of HA-AKI when treating moderate-to-severe pain.