Pathology of the ligamentum teres is rarely diagnosed. We describe the classification of the lesions seen at hip arthroscopy based on a group of 20 patients. Three groups are noted: complete rupture, partial rupture, and the degenerate ligamentum. The complete ligamentum teres rupture group had a history of either major trauma or surgery and had a high incidence of other hip pathology such as labral tears and articular damage. The partial ligamentum rupture group presented with a long history of ill-defined hip pain. Minor associated hip abnormalities were seen at arthroscopy. Degenerate ligamentum teres rupture presented with symptoms of the underlying osteoarthritis. Debridement or washout was performed but, at 2 years, patients had severe persistent symptoms or had had a joint replacement.