Recently, robot-assisted laparoscopic prostatectomy (RALP) has become a widely accepted surgical alternative for the treatment of prostate cancer. The intravesical migration of clips is a rare surgical complication of RALP. From March2013 to July 2018, 320 patients underwent RALP at our hospital. Migration of a Hem-o-Lok clip into the urinary bladder occurred in 4 of the 320 patients (1.3%). We analyzed these 4 patients in terms of subjective symptoms, intra- and post-operative findings, site of the migrated clip, and its treatment. The mean duration from RALP to the diagnosis was 13.8 months (2-26 months). The main symptoms due to migrated clips were : narrowed urinary stream, perineal pain, gross hematuria, and painful urination. In all cases, the size of the migrated clip was medium-large, and the events developed on the side contralateral to the first assistant. The clips were transurethrally removed using a Holmium-laser in 2 patients, and spontaneous excretion was observed in 1. The remaining patient has been asymptomatic and is being conservatively observed. In order to prevent the migration of clips used during RALP, the size of the clips and direction of the clip tail may be important. The first assistant should place the clips carefully, especially on the contralateral side.