Fluorine-18fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) has become a very useful technique for the therapy monitoring of patients with lymphoma. It provides unique information about the metabolic behavior of the disease independent of morphological criteria. In recent years, [18F]FDG-PET has proven to be a technique with high sensitivity for the detection of residual tumor. Therefore, [18F]FDG-PET seems to be the ideal tool for the evaluation of treatment response. However, most recent published studies included both HD and NHL, although [18F]FDG-PET scan results in Hodgkin's disease (HD) has a different impact than in Non Hodgkin's Lymphoma (NHL). In this paper, we summarize our findings on the role of [18F]FDG-PET in the therapy evaluation of lymphoma patients in a large group of patients and highlight the differences between the interpretations of the results of HD and NHL patients. Finally, a strategy for the implementation of [18F]FDG-PET in the management of lymphoma patients is proposed.