A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether positron emission tomography is useful in the diagnosis and prognosis of malignant pleural mesothelioma (MPM). Altogether 136 papers were found using the reported search, of which 15 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that fluorodeoxyglucose-positron emission tomography (FDG-PET) accurately differentiates benign from malignant pleural disease, helps detect recurrence and provides prognostic information in terms of staging, survival and mortality. Eleven studies evaluated the role of FDG-PET in the diagnosis and prognosis of MPM. Malignant disease had a higher standardised uptake value (SUV) (6.5 ± 3.4 vs. 0.8 ± 0.6; P < 0.001) than benign pleural disease. Shorter median survival (9.7 vs. 21 months; P = 0.02) was associated with high SUV (>10) than low SUV (<10). PET accurately upstaged 13% and downstaged 27% of cases initially staged with computed tomography (CT). In patients undergoing chemotherapy, higher total glycolytic volume led to a lower median survival (4.9 vs. 11.5 months; P = 0.09), while a decline in FDG uptake was associated with a longer time to tumour progression (14 vs. 7 months; P = 0.02). Four studies observed the role of FDG-PET-CT in the diagnosis and prognosis of MPM. SUV was found to be higher in MPM compared to benign pleural disease (6.5 vs. 0.8; P < 0.001). A higher SUV(max) was observed in primary pleural lesions of metastatic (7.1 vs. 4.7; P = 0.003) compared to non-metastatic disease. Patients who underwent surgery had equivalent survival to those excluded based on scan results (20 vs. 12 months; P = 0.3813). One study compared the utility of PET and PET-CT in the diagnosis and prognosis of mesothelioma. PET-CT was found to be more accurate than PET in terms of staging (P < 0.05) disease. Overall, PET accurately diagnoses MPM, predicts survival and disease recurrence. It can guide further management by predicting the response to chemotherapy and excluding surgery in patients with extrathoracic disease. Combined PET-CT has additional benefits in accurately staging disease.