Purpose We compared the safety and efficacy of bipolar transurethral resection and monopolar resection for bladder tumors. Materials and Methods A single center, parallel arm, randomized, controlled trial was performed from May 2011 to August 2012. All patients with suspected bladder tumors were eligible for study inclusion. Those who refused consent and those undergoing routine restaging transurethral resection of bladder tumor were excluded from analysis. The primary end point was the incidence of obturator jerk. Secondary study outcomes included the decrease in hematocrit, rates of recoagulation and transfusion, bladder perforation, decrease in sodium, resection syndrome and resection time. Pathological quality was assessed by comparing deep muscle and the degree of severe cautery artifact in the 2 arms. Results A total of 257 transurethral resections were performed during the study period. After exclusion 147 patients were randomized, including 75 in the monopolar arm and 72 in the bipolar arm. There were 6 and 4 protocol violations in the monopolar and bipolar arms, respectively. Intent to treat and per protocol analyses were performed. The incidence of obturator jerk was greater in the bipolar arm (60% vs 49.2%, p = 0.27). There was no significant difference between secondary outcomes. The only significant difference was a significantly lower incidence of severe cautery artifact in the bipolar arm (25% vs 46.7%, p = 0.0096). Conclusions Bipolar transurethral resection of bladder tumor was not superior to monopolar resection with respect to obturator jerk, bladder perforation and hemostasis. There was a significantly lower incidence of severe cautery artifact after bipolar resection.