Nonaccidental trauma can be difficult to differentiate from osteogenesis imperfecta (OI), especially in the face of multiple fractures. When nonaccidental trauma is being considered, medical causes of injury must be ruled out. In this report, we discuss the case of an 11-month-old female infant who presented with a transverse femur fracture and was also found to have a healing transverse humeral fracture and rib fractures. Medical causes of the fractures were investigated by performing an analysis of urine organic acids, serum amino acids, vitamin D, parathyroid hormone, ceruloplasmin, copper, and blood sequencing for COL1A1 and COL1A2. A mutation of the gene COL1A1 was found, which is consistent with OI type I.