Purpose: To compare suprapubic open prostatectomy (SOP) and a novel SOP with transurethral adjustment of residual adenoma and bleeding (TURARAB) for large sized prostates. Methods: Between March 2010 and March 2014, 49 patients with symptomatic BPH (>100 g) were scheduled for SOP or SOP with TURARAB. The patients were subdivided into two groups. In Group I, each patient underwent SOP. In Group II, each patient underwent SOP with TURARAB. Additional transurethral resection of residual adenoma and bleeding control were done through the urethra after enucleation of the prostate adenoma by SOP. Prior to intervention, all patients were analyzed by preoperative complete blood count, blood chemistry, prostate specific antigen, International Prostate Symptom Scores, and transrectal ultrasound of the prostate and uroflowmetry. SOP was performed by a suprapubic transvesical approach via a midline incision. The bladder neck mucosa was circularly incised to expose the prostate adenoma, and the plane between the adenoma and surgical capsule was developed by finger dissection. In addition, in Group II TURARAB was performed using Urosol. Postoperative outcome data were compared in the 1st month and 3rd month. Results: There were no statistically significant differences in baseline characteristics between the two groups. Group I required a longer operative time than Group II. Blood transfusion during the operation was unnecessary due to the short amount of time available to control arterial bleeding in the prostatic fossa leading to a marked decrease in perioperative bleeding in Group II. Postoperative voiding function improved significantly in both groups. Conclusions: Even for large prostate glands, our novel procedure appears to be an effective and safe operation to reduce operation time, bleeding, and complications.