Abstract Background and Aims Fracture risk evaluation has recently been integrated into the 2017 KDIGO CKD-MBD (Chronic Kidney Disease- Mineral and Bone Disorder) guideline and its 2021 Spanish endorsement. It is now suggested to test bone mineral density (BMD) to assess fracture risk “if results will impact treatment decisions”. In fact, multiple new prospective studies have now documented that lower BMD predicts incident fractures in patients with CKD G3a–G5D. However, we scarcely know current real clinical practice in this population. Thus, the aim of the ERCOS (“Enfermedad Renal Crónica OSteoporosis”) study was to describe the clinical profile of patients with CKD who had been diagnosed of osteoporosis in outpatient Nephrology and Rheumatology clinics in Spain. Method ERCOS is a descriptive, observational, and multicenter Spanish study. Patients were recruited by consecutive sampling from 15 different Spanish hospitals. Osteoporosis characteristics (history of fragility fracture, BMD and other fracture risk factors), associated comorbidities, biochemical parameters and treatment were analyzed. Results A total of 163 patients (median age 77 years old) were included. Most were women (71.2%) and 98.3% of them were postmenopausal. Hypertension was the most frequent comorbidity (87.1%) and “attributed” cause of CKD (43.2%). Diabetes mellitus and cardiovascular disease were present in 35.6% and 29.4% of patients, respectively. Median estimated glomerular filtration rate was 36 ml/min/1.73 m2 [creatinine 1.48 mg/dl (95% CI 1,2-2)]. 38% of patients were G5D CKD patients (95.2% undergoing hemodialysis). 37.7% of patients had had a fragility fracture after the diagnosis of CKD (vertebral 52.5%, hip 24.6%, wrist 21.3%, humerus 16.4%, among others). Importantly, despite the diagnosis of osteoporosis, only 60.1% of the patients received specific treatment (mainly bisphosphonates or denosumab). Moreover, antiosteoporotic treatment was much more frequently prescribed by rheumatologists (46.9%), internal medicine physicians (23.5%), and only 13.3% was prescribed by nephrologists. 19.4% of patients suffered from fragility fractures even after initiating specific treatment. Conclusion Most patients with moderate and severe CKD with osteoporosis were old postmenopausal women with a high prevalence of diabetes or cardiovascular disease. Although about 40% had even suffered a fragility fracture, there is a high treatment gap, especially relevant among nephrologists. A call to action and to avoid existing therapeutic nihilism seems necessary, expanding the knowledge of the new more proactive guidelines and homogenizing the care and therapeutic approach in these patients.