Although osteoporosis is a disease of later life and it's major complication, fractured femur, usually occurs after the age of 75, this age group has been excluded from most trials of treatment.A group of 46 younger osteoporotic patients, median age 67yrs (range 60-74) were compared with a group of 27 older patients, median age 79 (range 75-87). The patients attended the same clinic and were treated with cycles of etidronate 400mgms for 14 days followed by effervescent calcium carbonate 1.25gm daily for 76 days together with appropriate counselling. Bone mineral density (BMD) was measured by DEXA scanning and repeated after 12 months treatment.Although BMD was higher in the younger group the differences were not significant. Improvement with treatment was proportionately greater in the older age group but again the difference between the two groups was not significant.We conclude that older subjects respond to cyclical etidronate/ calcium therapy at least as well as younger subjects