Even though various kinds of diagnostic and therapeutic measures have been used for the detection and cure of the acute osteomyelitis, this disease is difficult to be eradicated in many clinical cases. However it is rather easy to treat once this disease can be detected in early stage. So far radiological examination and many kinds of maneuvers including blood culture, clinical laboratory, xeroradiography, computed tomography have been performed for the early detection of this disease but invalid in the most cases. Recently some authors reported that the bone scanning was useful for the early detection of acute osteomyelitis, but this method also had difficulty in differential diagnosis and uncertaninty of its activity. This study aims to try to find methods of early detection of acute osteomyelitis. Experimental osteomyelitis was developed by the inoculation of Staphylococcus aureus to proximal tibias of 39 young rabbits already sclerosed by solution of sodium morrhuate. By comparing the clinical, radiological, bacteriological and laboratory findings in sequence from 2 days to 7 weeks after inoculation, the following results were obtained. 1. The incidence of experimental osteomyelitis after inoculation of staphylococcus aureus SNUH-S-188 in suspension of 1×10(7) colony forming units was 84%, 74%, and 79% in radiological, blood culture and pathologic examination respectively. 2. The leucocytosis was noticed only in early stage and slight degree of anemia was found during the 1st and 2nd weeks after inoculation. The sedimentation rate was increased only in early acute stage and same was eosinophil count. The leucocyte alkaline phosphatase(LAP) and platelet count. showed no significant abnormal changes. 3. Lymphocyte and eosinophil turned over from normal and eosinophil was predominant in experimental osteomyelitis. 4. Serum calcium, phosphorus, total protein and albumin showed significant decrease in all stages and was conversely paralle1 to changes in groin temperature. The level of BUN was normal indicating normal kidney function in experimental osteomyelitis. 5. Even though the enzymes of which showed no significant changes enrolled alkaline phosphatase and serumgluiamicoxalic-transaminase(S-GOT), but some increa.e was attained to 27% and 44% respectively. 6. It is important and significant to find continuous increase of lactic dehydrogenase (LDH) and creatine phosphokinase (CPK) since 48 hours after inoculation and author, think these will be the reliable and sensitive indices in early detection of the development of osteomyelitis and efficacy of therapeutic measures.