['Malignant pleural Mesothelioma (MPM) is a very rarely encountered tumor in the normal population.', 'To investigate the variations in incidence of MPM in Southeast region of Turkey.', 'We retrospectively investigated the data of 161 MPM patients who were diagnosed from January 2000 to December 2009. The residential areas were determined according to asbestos exposure which plays a role in MPM etiology; previously reported as having asbestos (Region 1) and asbestos has not been determined previously (Region 2).', 'One hundred nine (109) of the patients (67.7%) included from the Region 1 and 52 of them (32.3%) included from the Region 2. MPM incidence of the last decade was 3.9/100,000 person/year for the whole region. In Region 1, 2000-2004 incidences was 12.6/100,000 person/year and 2005-2009 incidences was 14.9/100,000 person/year. In Region 2, 2000-2004 incidences was 0.4/100,000 person/year and 2005-2009 incidences was 1.0/100,000 person/year. According to the recently conducted incidence studies in our region, MPM incidence increased in region 1 and decreased in region 2. The number of patients applying to our hospital has increased in the last three years.'] Has the incidence of mesothelioma decreased for the last twenty years in Southeast region of Anatolia?