Purpose <p>Early postoperative intravesical chemotherapy after transurethral resection of bladder tumor aims to eliminate free-floating tumor cells and reduce recurrence. However, dwell time may be influenced by postoperative discomfort, which can differ according to anesthesia type. This study evaluated the impact of spinal versus general anesthesia on dwell time and tolerability of early intravesical epirubicin.</p> Methods <p>In this prospective observational study, 106 patients undergoing transurethral resection of bladder tumor for non–muscle-invasive bladder cancer received early intravesical epirubicin (50&#xa0;mg/50 mL). Patients were divided into spinal (<i>n</i> = 42) and general anesthesia (<i>n</i> = 64) groups. Dwell time, early catheter unclamping, pain scores (VAS at 30, 60, 90, 120&#xa0;min.), voided urine volume, and complications were compared between the groups.</p> Results <p>Baseline demographics, tumor characteristics, and operative duration were similar between groups. Mean dwell time was significantly longer in the spinal anesthesia group compared to general anesthesia (97.8±27.9 vs. 73.6±32.1&#xa0;min., <i>p</i> = 0.009). The rate of completing the target time was higher in the spinal anesthesia group (%32.1 vs. %9.1, <i>p</i> = 0.003). VAS scores at 30 and 60&#xa0;min were significantly lower in the spinal group (3.78 ± 2.04 vs. 5.24 ± 2.46, <i>p</i> = 0.001 and 5.23 ± 2.48 vs. 6.47 ± 2.21, <i>p</i> = 0.016, respectively), whereas 90- and 120-minute scores showed no significant differences (5.67 ± 2.08 vs. 6.63 ± 1.93, <i>p</i> = 0.109 and 6.19 ± 2.13 vs. 6.40 ± 1.58, <i>p</i> = 0.773, respectively). No major postoperative complications were observed.</p> Conclusions <p>Spinal anesthesia is associated with longer dwell time and better early tolerability of intravesical epirubicin compared to general anesthesia, without increasing complication rates. These findings suggest spinal anesthesia may optimize early intravesical chemotherapy efficacy.</p>