Background: Acupuncture seems to improve cognitive function in experimental models and to reduce agitation in dementia. The addition of acupuncture to standard-of-care (SOC) may improve clinical outcomes related to delirium in hospitalized older adults. Methods: This pragmatic open-label randomized-controlled trial evaluated 81 older adults hospitalized in an internal medicine ward and diagnosed with delirium. Fifty were randomized to daily acupuncture combined with SOC and 31 to SOC only for up to 1 week. Delirium was diagnosed using Confusion Assessment Method (CAM) tool, and its severity was assessed by the long CAM-Severity (CAM-S) tool. The primary study outcome was delirium resolution evaluated as time-to-first delirium remission (over 7 days) and the number of days spent delirium-free. Results: Time-to-first delirium remission was shorter in the acupuncture arm as compared to the SOC only arm (p < 0.001). A multivariate Cox regression analysis showed a shorter time-to-first remission of delirium in the acupuncture arm as compared with SOC arm [Hazard Ratio 0.267 (95% CI 0.098-0.726, p = 0.010)]. In the 7 days of evaluation, a significantly higher number of delirium-free days was found in the acupuncture arm compared to the SOC arm (p < 0.001), and CAM-S sum from day 2 to day 7 of evaluation was significantly lower in the acupuncture group compared to the control group (p = 0.002). No adverse safety event was found in the acupuncture group. Conclusion: Acupuncture seems to be safe and effective in the treatment of delirium in older patients hospitalized in internal medicine departments.