Objectives: To report and discuss a case of pneumonia with tibia osteomyelitis in a 79-y-o woman, and how UTI complicated the disease process and influenced the recovery.Methods: This patient had been diagnosed to have tibia osteomyelitis by diagnosed to have tibia osteomyelitis by changes. Diagnosis of pneumonia was made several weeks after chronic osteomyelitis had been treated. Significant improvement of clinical symptoms from pneumonia was achieved with appropriate antimicrobial therapy. However, UTIs complicated the treatment process and lengthened her hospital stay.Results: This patient's complaints and clinical symptoms were resolved gradually.Conclusion: UTI is an ordeal for a critically ill patient. Prevention of UTI is essential for the sake of patient health and medical costs.