Asbestos-related diseases, including asbestosis, benign pleural diseases, lung cancer, other types of cancer, and especially malignant mesothelioma (MM), still represent an enormous problem all over the world and are among the most investigated occupational diseases. Considering that MM is a highly aggressive and severe malignant cancer of pleura, peritoneum and other serosal surfaces, new blood biomarkers for earlier diagnosis, following response to treatment and disease progression, have been intensively investigated. Several studies suggested that soluble mesothelin-related peptides, fibulin-3, survivin, osteopontin, vimentin, calretinin, and many others could be helpful in diagnosis, detecting the progression of MM and evaluating tumour response to treatment; however, these biomarkers have not been validated in clinical practice. Therefore, search for novel better stand-alone or composite biomarkers is under way. The aim of this chapter is to present the importance of blood biomarkers in evaluating the risk of developing asbestos-related diseases, early diagnosis, following the response to treatment and progression of these diseases, with special emphasis on MM.