Aims: To investigate the potential of biological þxation of cementless total hip prosthesis in patients over 75 years old, with diagnosed osteoporosis. Methods: Between 1994Ð2000, 30 patients (mean age 77.3 years) underwent total hip arthroplasty (THA). Twenty-two (22) patients, 10 male and 12 female, were found at the last follow-up, which ranged from 1.5–7 years (mean follow-up, 3 years). THA was performed due to primary osteoarthritis (n=16), subcapital fracture (n=4), or dysplastic hip (n=2). Eight (8) smooth, tapered design (CLS) and 14 proximally porous coated prostheses were implanted. Singh index was used for the evaluation of osteoporosis and modiþed Harris Hip Score was used for the clinical evaluation of each patient. Modiþed Wixon score was used for the evaluation of stability probability of the tapered stem. Engh score was calculated for the evaluation of osseointe-gration of the porous coated implants. Results: Pre and post-operative mean Singh index was grade 4. Mean modiþed Harris Hip Score at the last follow-up was 88.6. For the CLS-Spotorno stem a stable þxation probability was calculated at 74.8%, while possible instability was calculated at 48.17%. Porous coated stems provided +13.45 mean Engh score, implying satisfactory þxation of the implant. Post-operative systematic complications are not reported, in contrast to 3 dislocations in the þrst post-operative period, which were treated by closed reduction. Conclusions: In patients over 75 years old, with possible cardiopulmonary disease, cementless total hip arthroplasty offers a reliable treatment, regardless the presence of osteoporosis. Satisfactory osseointegration and absence of systematic complications is compromised by the high cost of titanium implants.