Osteomyelitis of the calvarial bones can cause serious complications such as brain abscess, due to the close proximity to adjacent brain structures. Development of the purulent secretion in surgery and traumatic scalp injuries must be considered as a possibility of osteomyelitis possibility. Generally gram positive, rarely gram negative bacteria and mix agents, can be isolated in infection. Especially chronic pyogenic osteomyelitis agents can be isolated from chronic infections such as tuberculosis. In cranial osteomyelitis diagnosis, radiological diagnosis has a very important place together with the clinical diagnosis. However, infection can usually show late findings radiologically. In treatment, antibiotic treatment is absolutely essential as well as removal of the infected part of the bone. Due to antibiotic treatment lasting between 6-12 weeks, organizing the antibiotic protocols according to the results of culture-antibiograms, which were provided from purulent secretions, has the most important role in the success of surgical treatment. In Proteus sp. infections, for choice of suitable treatment, determination of the type of bacteria is important. For exact diagnosis, histopathological examination of the bone tissue must be carried out. In this report, a case with cranial osteomyelitis caused by Proteus vulgaris which is a gram negative bacteria causing anaerobic infections and classified in the Enterobacteriaceae family is presented. The patient was treated with surgery and appropriate antibiotics. Early recognition of this condition, planning the best treatment strategy and taking precautions to prevent complications, is mandatory for a better outcome. [ABSTRACT FROM AUTHOR]