Osteomyelitis of the odontoid process is a rare disease and Staphylococcus aureus is the usual causative organism. We present a case caused by a synergistic infection with Staphylococcus aureus and Proteus mirabilis, which has not been reported previously. A high index of suspicion is required for diagnosis, and early institution of broad antimicrobial therapy, including agents active against gram-negative organisms, is mandatory.