A 28-year-old male visited our hospital with complaint of lower abdominal pain, hematuria and urinary urgency. He had inserted a fishing line into the bladder transurethrally for sexual masturbation. The fishing line was made of nylon and was 1.66 mm in diameter. He could not remove it by himself due to pain. Retraction of the line with forceps was impossible ; the intricately entangled line was blocked at the bladder neck. We fragmented the line by a transurethral resection system operated in saline (TURis) and removed it transurethrally. The total length of the fishing line in the bladder reached 464 cm. TURis was useful for fragmentation of this foreign object, which consisted of electro-resistant material and could not be cut by conventional TUR.