Aim of the study: The aim of this study was to assess the diagnostic value, of plain X-ray, triple phase bone scan, and 99mTc-HMPAO labeled leukocytescintigraphy in diagnosis of bone infection, especially in evaluation of infectionin patients with symptomatic bone and joint prostheses.Materials and Methods: This study included 91 sites suspected to have boneinfection were included. Patients were divided into two major groups; Group I:49 sites with current endo-prosthesis; Group II: 42 sites with no prosthesis.Images of labeled leukocyte were acquired at 3 different time points after theinjection of the labeled leukocytes: 30 min, 4 h, and 24 h. Also all patients hadtriple phase bone scan, and plain X-ray. The final diagnosis of infection wasbased on clinical, surgical, and bacteriologic data and follow-up.Results: The overall sensitivity for X-ray radiography was reported in ourstudy to be 34.9% and specificity was 47.9%. Bone scan was sensitive fordetection of osteomyelitis (overall sensitivity of 95.4 %) but it had a low overallspecificity of only 45.8%. The reported overall sensitivity, specificity andaccuracy for Labeled WBCs were 86 %, 91.7% and 89% respectively.99mTc-HMPAO labeled WBCs showed better sensitivity, specificity andaccuracy in the group with current prostheses reaching 95%, 93.1% and 93.9% respectively. Whereas, the plain x-ray showed sensitivity of 40%, specificityof 41.4%, and accuracy of 40.8% and the sensitivity, specificity and accuracyof the triple phase bone scan were 90%, 62%, and 73.5% respectively.In the group with no prosthesis, the sensitivity, specificity and accuracy of thelabeled WBCs modality were 78.3 %, 89.5%, and 83.3% respectively. Whilethe plain radiographs showed sensitivity, specificity and accuracy of 30.4%,57.9%, and 42.9% respectively and the sensitivity, specificity and accuracy ofthe triple phase bone scan were 100%, 21.1% and 64.3% respectively.Conclusion: 99mTc-HMPAO-leukocyte appears to be an effective andsensitive agent to detect skeletal infections. It can be used as an alternative toconventional agents for diagnosis of bone infections.