Ovarian endometrioma is quite common among women of reproductive age but rarely exceed 6 cm in diameter. Ovarian endometrioma exceeding 10 cm in dimension, often referred to as giant endometrioma, is rare and can pose a diagnostic dilemma to clinicians. We present a 33-year-old single nullipara referred to our facility with a 3-year history of recurrent abdominal pain, abdominal swelling, and difficulty in breathing. The challenges in making diagnosis of a huge ovarian endometrioma are highlighted and the literature on huge ovarian endometrioma reviewed.