PURPOSE F18 FDG PET CT is an established molecular imaging technique most commonly used in the diagnosis and staging of oncological conditions. A rapidly growing clinical application of PET CT is in the investigation of inflammatory and infectious diseases. A review of PET CT scans performed in a tertiary referal centre is presented illustrating its applications and clinical value in the evaluation of suspected or known inflammatory conditions. METHOD AND MATERIALS a retrospective case review of 59 patients was carried out. all patients underwent PET CT scanning after multiple diagnostic investigations failed to determine a diagnosis. RESULTS PET CT was useful in all 59 cases; revealing malignancy in 11 (2 of whom had associated myositis), systemic vasculitis in 9, inflammatory arthropathy in 5, infectious/other inflammatory process in 8 and helped to exclude malignant or inflammatory process in 26 patients. CONCLUSION F18 FDG PET CT has the potential to develop into a valuable tool in the diagnostic work up of a variety of infectious, inflammatory and paraneoplastic type conditions. there is a growing body of evidence to support its earlier use in the investigation of patients presenting with these conditions, enabling earlier diagnosis and treatment. CLINICAL RELEVANCE/APPLICATION FDG PET CT should be considered early in the diagnostic work up of patients with inflammatory type, often vague, symptoms and signs.