Despite the remarkable reduction in the incidence of lung cancer among men in many developed countries, there has been a fourfold increase in lung cancer in women over the past 30 years associated with a rising trend in female lung cancer related mortality. Early diagnosis and appropriate treatment of lung cancer are two important determinants of prognosis and overall disease outcome. Functional imaging has recently gained a prominent role in the management of numerous pulmonary malignancies. The successful introduction of 18F-fluorodeoxyglucose (18F-FDG) along with PET/CT image fusion has revolutionized diagnostic imaging in lung cancer. Currently, 18F-FDG PET/CT is considered the most precise diagnostic test for a wide range of pulmonary malignancies. This is primarily attributed to its unique ability to assess the global metabolic state of each individual tumor. In fact, the high sensitivity and the whole body mode of data acquisition are two critical advantages that favor 18F-FDG PET/CT over other cross sectional imaging modalities like CT and MRI. Noteworthy, however, is the complementary role of dynamic contrast enhanced CT in characterizing indeterminate pulmonary nodules and adrenal lesions. Besides its distinguished diagnostic potentials, especially in unmasking occult tumor foci, 18F-FDG PET/CT can precisely delineate the locoregional tumor burden for an accurate radiotherapy treatment planning. Furthermore, PET can offer reliable prognostic information since the avidity of both de novo and previously treated cancerous lesions to 18F-FDG has been shown to correlate with the overall disease outcome and patient survival. In the near future, further brilliant horizons are expected since the development trials of other radiotracers that target tumor proliferation, apoptosis, and hypoxia are emerging.