Mysophobia - fear of contamination is one of the most prevalent types of the obsessive-compulsive disorder (OCD). "Moral mysophobia" is a ritual of cleanliness and avoidant behavior due to unpleasant obsessive thoughts. The presence of "moral" component in this subtype of contamination fear is supposed to cause high level of treatment resistance. The study included 16 patients with "moral mysophobia". The psychopathological structure of the phenomenon was described. Delusional symptoms and mental automatisms were found to contribute to its development. The analysis of schizophrenia course suggested that the development of "moral mysophobia" in schizophrenia was based on prominent negative symptoms.