PURPOSE: To evaluate the functional changes, postop delirium and complications after cemented bipolar hemiarthroplasty for the femur neck fractures in patients aged around ninety. MATERIALS AND METHODS: Between May 1995 and April 2002, of the twenty seven patients, 17 who follow-up for at least one year were included in this study. Walking ability, activity of daily living, mental status, chronic illness, postoperative delirium and complications were evaluated retrospectively using Yoon's walking class, ADL scale, MMSE-K score, ASA classification, DSM IV respectively. RESULTS: The walking ability was decreased to 2.4 from 3.3 tendency of reliance in ADL scale was increased to 8.3 from 4.5, MMSE-K score was decreased to 15.9 from 21.7. There was no significant change in status of chronic illness. Postoperative delirium occurred in eight (47%) cases and all of them recovered completely. complications included bladder problem in eleven (66%) cases, temporary respiratory distress in two (12%) cases, hip dislocation in two (12%) cases, infection in one (6%) case. Overall thirteen (78%) cases were able to walk with supports. CONCLUSION: This study indicates that physicians treation femur neck fractures in patients aged around ninety must anticipate worsening of the functional changes more especially in regard to walking level, activity of daily living and mental status, little changes of chronic disease status, complete recovery of postop delirium and high complication rate