We report the case of a 33-year-old man who suddenly died with the symptoms of a cardio-respiratoric insufficiency. As cause of death we found pulmonary alveolar microlithiasis (MAP) with intra-alveolar calcifications and fibrosis of the alveolar margin. It is not known whether this diagnosis was found during lifetime. In our forensic experience we never met a case of this rare illness causative of sudden natural death.