A 71-year-old Japanese woman complained of right upper abdominal fullness and pain. Computed tomography revealed a huge cyst in the right lobe of the liver, measuring 16 cm in diameter. She underwent laparoscopic deroofing of the liver cyst. On operation, needle aspiration of the cyst yielded clear serous fluid without any bile contamination. However, after the cyst was deroofed with laparoscopic coagulating shears, bile leakage was recognized from a tiny orifice in the cyst cavity. A catheter was inserted via the orifice for cholangiography, which demonstrated a communication with the biliary tract. The orifice was easily closed with a laparoscopic suturing device. Operation time was 5 hours and 30 minutes, and blood loss was 300 grams. Pathological examination of the liver cyst was consistent with a simple cyst. The postoperative course was uneventful, and the patient has had no recurrence to date at 13 months. Laparoscopic deroofing is a recommended treatment for a liver cyst even in the presence of cystobiliary communication.