Ten cases of erotomania with a clinical picture determined by isolated erotic delusion have been examined. Three stages in the disease course (catathymic, delusion systematization and residual) have been recognized. While diagnostic evaluating, an accordance of the disorders with Clerambault's syndrome in disease debut and an increase of erotomanic paranoia symptoms in pathological process development were taken into account. Premorbid personality abnormalities of schizoid spectrum, catathymic character of delusion with affective component in its formation, narrow range and concrete content of persecution ideas, expansive manifestations in the patient behavior and favorable outcome were found to characterize the isolated erotomania. The existence of special marginal types of erotomania, not corresponding to atypical paranoia spectrum (paranoia, paranomic schizophrenia) is assumed. Most of the patients were diagnosed as affected with schizotypic disorder (slow-progredient schizophrenia).