Aim: This study was designed to evaluate the use of ultrasound in diagnosis of infection and tumour of long bones. Methodology: Patients referred from the orthopaedic unit with doubt regarding long bone clinical and/or radiological signs which could be tumour or infection were enrolled in this study. Analysis of ultrasound characteristics included presence of pericortical fluid over normal cortex well away from the primary lesion, wavy contour sign (fluid tracking in and out muscle planes), subperiosteal fluid and soft tissue mass displacing adjacent muscle planes. Results: Fourteen out of 15 patients with confirmed osteomyelitis were diagnosed by ultrasound examination. Ultrasound as a diagnostic tool has a sensitivity of 93% and specificity of 100%. The most accurate indicator was pericortical fluid noted up to several centimetres from the long bone abnormality seen on plain x-rays. Conclusion: Ultrasound is a safe, fast, cost-effective imaging modality that can play an important role in diagnosis of osteomyelitis as it then serves as a tool for ultrasound guided aspiration.