We present the case of bilateral diaphyseal sclerosis in a 60-year-old woman with bilateral midfemoral pain for the last 8 years. There was no relevant medical or family history. Imaging work-up showed diaphyseal asymmetric intramedullary sclerosis with cortical thickening. No periosteal reaction or other soft-tissue abnormalities were apparent. Laboratory findings were also unremarkable, except for a mild elevation of erythrocyte sedimentation rate. Findings were strongly suggestive of intramedullary osteosclerosis, which was confirmed histologically. Intramedullary osteosclerosis is a benign rare condition and clinical awareness is important when considering the extensive differential diagnosis of disorders causing long bone sclerosis.