Summary Despite the availability of efficient drugs to prevent osteoporotic fractures, only a minority of women receives osteoporosis therapy after a fracture. The high treatment gap in our cohort consisted of unselected volunteer patients highlights the urgent need of additional education, especially for the medical profession, regarding the risk-benefit balance of treatment. Introduction Despite the availability of efficient drugs to prevent osteoporotic fractures, only a minority of women receives osteoporosis therapy after a fracture, with a treatment gap around 80%. This can have dramatic consequences for patients and the healthcare systems. Methods In this study based on longitudinal data from the FRISBEE (Fracture RIsk Brussels Epidemiological Enquiry) cohort of 3560 volunteer women aged 60 to 85 years, we evaluated the 1-year treatment gap after a first major incident fragility fracture. Results There were 386 first validated fragility fractures, 285 major osteoporotic fractures (MOF) and 101 “other major” fractures. The rate of untreated patients was 85.0% (82.8% for MOF versus 91.0 % for “other major” fracture sites) ( p  = 0.04), with a lower rate for spine (70.5%) and hip (72.5%) versus shoulder (91.6%) and wrist (94.1%) ( p  < 0.0001). More specifically, the treatment gap for patients with osteoporosis, defined by a T -score < − 2.5 SD was 74.6% versus 76.5% for patients with osteoporosis defined by the presence of hip, shoulder, or spine fractures, independently of DXA results. When considering age groups, the rate of untreated women was 87.9% for women 60–70 years old, 88.2% between 70 and 80 years and 77.8% above 80 years ( p  = 0.03), with a greater difference between women who were younger or older than 80 years at inclusion: 88.1% versus 77.8% ( p  = 0.009). A diagnosis of osteoporosis ( p  = 0.01) and age ( p  = 0.03) were the only clinical risk factors (CRFs) significantly associated with treatment initiation. Conclusions This study highlights the urgent need of additional education, especially for the medical profession, regarding the risk-benefit balance of treatment.