Background: Opioid titration is necessary to achieve rapid, safe pain relief. Medication can be administered via patient-controlled analgesia (PCA) or by a healthcare provider (non-PCA). We evaluated the efficacy of intravenous PCA versus non-PCA hydromorphone titration for severe cancer pain (≥7 at rest on the 11-point numeric rating scale [NRS]). Patients and Methods: Patients with severe cancer pain were randomized 1:1 to PCA or non-PCA titration, stratified by opioid-tolerant or opioid-naïve status. The PCA pump was set to no continuous dose, with a hydromorphone bolus dose 10% to 20% of the total previous 24-hour equianalgesic (for opioid-tolerant patients) or 0.5 mg (for opioid-naïve patients). For the non-PCA group, the initial hydromorphone bolus dose was identical to that in the PCA group, with the subsequent dose increased by 50% to 100% (for NRS unchanged or increased) or repeated at the current dose (for NRS 4–6). Hydromorphone delivery was initiated every 15 minutes (for NRS ≥4) or as needed (for NRS ≤3). The primary endpoint was time to successful titration (TST; time from first hydromorphone dose to first occurrence of NRS ≤3 in 2 consecutive 15-minute intervals). Results: Among 214 patients (PCA, n=106; non-PCA, n=108), median TSTs (95% CI) were 0.50 hours (0.25–0.50) and 0.79 hours (0.50–1.42) for the PCA and non-PCA groups, respectively (hazard ratio [HR], 1.64; 95% CI, 1.23–2.17; P=.001). TSTs in opioid-tolerant patients were 0.50 hours (0.25–0.75) and 1.00 hours (0.50–2.00) for the PCA and non-PCA groups, respectively (HR, 1.92; 95% CI, 1.32–2.78; P=.003); in opioid-naive patients, TST was not significantly different for the PCA versus non-PCA groups (HR, 1.35; 95% CI, 0.88–2.04; P=.162). Pain score (median NRS; interquartile range) over 24 hours was significantly lower in the PCA group (2.80; 2.15–3.22) than in the non-PCA group (3.00; 2.47–3.53; P=.020). PCA administration produces significantly higher patient satisfaction with pain control than non-PCA administration (P<.001). Conclusions: Intravenous hydromorphone titration for severe cancer pain was achieved more effectively with PCA than with non-PCA administration.