Sleep disorders in psychiatric pathology is an incontestable clinical reality. They are considered either psychiatric comorbidities or predisposing factors to other psychiatric disorders. The frequency of sleep pathology in psychiatry is different reflected in literature. Using questionnaires and interviewing methods, the authors do a transversal investigation, analyzing all sleep disorders found in 309 patients with different psychiatric pathologies from “Socola” Universitary Hospital Iasi. Conclusions: 85 % of psychiatric patients have sleep disorders; almost 1/3 of them are not aware of their sleep pathology and almost none of the patients respect any kind of sleep hygiene; 2/3 of patients use or make abuse of hypnoinductor drugs, abuse who is frequently hidden by psychotropic drug use. This statistics reveals more interesting aspects, which are very helpful for the psychiatrist in elaborating therapeutical strategies for each case of psychiatric and its associated sleep disorder.