Malignant mesothelioma (MM) is an aggressive tumour affecting the mesothelial surfaces of the pleural and peritoneal cavities and, rarely, the pericardium and the tunica vaginalis testis. Despite a ban of asbestos in many industrialized nations, the present high incidence of MM is expected to continue, due to the long latency period between first asbestos exposure and occurrence of disease, making it an important health issue for the future. The diagnosis of M can be difficult, both from a clinical and pathological perspective. It is not unusual for patients to undergo several medical investigations without definitive diagnosis early in their course of illness. Understandably, there is intense interest in the discovery of markers that can be assessed in pleural effusions, histological specimens, and serum to assist with the difficult early diagnosis of MM. Considering the primary aetiological role of asbestos, there is theoretically an easily identifiable target population for screening with a biomarker with adequate sensitivity and specificity or with a combination of biomarkers. In this review we focus on biomarkers that have been examined in the setting of either early diagnosis ofMMin symptomatic patients or screening of asbestos-exposed individuals.