Salmonella infection predominantly causes four clinical syndromes: enteric fever, gastroenteritis, bacteremia, and asymptomatic carrier state. Salmonella osteomyelitis is an extremely rare manifestation of salmonella infection except in children with hemoglobinopathies. Salmonella osteomyelitis has been reported to mostly affect the diaphysis of long bones and lumbar spine. Here, we describe a case of salmonella osteomyelitis of the right 6th rib in a 74-year-old woman who presented with breast pain, swelling, high fever and local heat. Her medical history showed myocardial infarction; namely, at the age of 71, the patient had undergone the drug-eluting stent placement in the left anterior descending artery. A computed tomography (CT) scan at the first visit to another hospital showed a mass in the chest that invaded the ribs. 18F-fluorodeoxyglucose-positron emission tomography-computed tomography imaging showed a lesion suspected to be a mammary malignant tumor. A needle biopsy revealed mesenchymal cells and suspected mammary sarcoma. However, the osteomyelitis of the rib was diagnosed when pyogenic tissue was observed during an open biopsy. The bacterial culture examination identified Salmonella enterica. Surgical drainage and antibiotic treatment were performed. Importantly, there was no evidence for any underlying disease that could lead to an immunocompromised status of the patient. To our knowledge, this is the first report of salmonella osteomyelitis of the rib presenting in an older female that required differentiation from a mammary tumor. Clinicians should consider rib osteomyelitis when they find swelling and local heat in the female's breast tissue and detect no cancerous tissue.