We compared bipolar and monopolar TURP in a prospective controlled study at two urology centers. The objective of the study was to establish whether there were differences between the two methods with regard to frequency of the transurethral resection (TUR) syndrome, amount of fluid absorbed during surgery, risk of hemorrhage, duration of postoperative catheterization and duration of hospitalization. The duration of surgery, improvement in maximum flow rate (Q-max), residual urine volume, International Prostate Symptom Score (IPSS) and Quality of Life (QoL) score were also compared. Overall, our study showed that there were no major differences between bipolar and monopolar TURP. During follow-up, the clinical efficacy of bipolar TURP has been maintained to the same degree as with the traditional method, with no significant differences for Q-max, IPSS and QoL scores after 1 year. Although the risk of developing TUR syndrome seemed to be smaller with bipolar resection (serum sodium change bipolar versus monopolar: þ 1.2 versus À0.1 mmol l À1 ), the bleeding tendency with both methods was the same (14.0 g l À1 hemoglobin loss after 1 day in both groups). On the basis of our findings, we think that the monopolar technique has still a place in TURP.